Photonics

http://www.ati.surrey.ac.uk/photonics

Professor Jeremy Allam

Professor of Ultrafast Optoelectronics

Short biography:

Jeremy Allam obtained his first degree in Physics from the University of Oxford, and his PhD from Surrey. After working for 2 years at AT&T Bell Laboratories and for 3 years as a postdoc sponsored by British Telecom, in 1990 he joined the newly-formed Hitachi Cambridge Laboratory where he formed a group working in Femtosecond Optoelectronics. In April 2000 he was appointed to a Chair in Ultrafast Optoelectronics.

Research Interests:

Jeremy's research interests include ultrafast carrier dynamics in semiconductors for optoelectronic devices, high-speed photonic measurement technologies, and high-field carrier transport. He has recently commissioned a a new ultrafast laser facility comprising laser oscillators and amplifiers, parametric oscillators and amplifiers, and frequency mixers, providing a capability for <100 fs optical pulses from UV to the mid-IR wavelengths.

Email: j.allam@surrey.ac.uk
Phone: 6799


Carbon Nanotube Photonics

Supervisor:  Professor Jeremy Allam
Co-Supervisors:   Dr. Alan Dalton, Dr Richard Curry

Type of project: Experiment

Major Aims
  • accurately quantify second- and third-order nonlinear coefficients in nanotube-doped polymers and glasses, and correlate with nanotube properties (diameters, chirality, etc)

  • investigate nonlinear propagation of ultrashort laser pulses in nanotube waveguides

  • demonstrate prototypical waveguide devices for ultrafast optical switching, sum-frequency generation, etc.

  • Techniques Used
    Nonlinear optical methods using femtosecond titanium-sapphire laser system, including:
  • Z-scan measurements

  • degenerate four-wave mixing

  • upconversion of propagating femtosecond pulses

  • Preparation of carbon nanotube samples, including:
  • growth of tubes

  • size selection

  • embedding in polymer waveguides, cavities, etc

  • Collaborations
    University of Southampton

    The Student Will Require
    • good hands-on skills with complex experiments

    • some knowledge of lasers and optics, and/or electronic and optical properties of solid-state materials

    • physical insight to guide the experiments performed

    • willingness to talk and collaborate with theorists, and industrial collaborators

    Project Description

    Dynamics of photogenerated excitons in isolated carbon nanotube. Inset: 1/sqrt(t) decay at low intensities
    The discovery that carbon atoms can form molecules with spherical and tubular geometry has provided researchers with a new class of materials with unique properties called carbon nanotubes (CNTs). In particular these CNTs possess remarkable mechanical and electrical properties that have been used to produce ultra-strong fibres and electron sources for displays amongst many other applications. Recently, studies on the optical properties of these materials have shown that they have much to offer in this area as well. These materials exhibit unique absorption and emission properties that can be controlled through changing the diameter of the carbon tubes. They also have significant potential through the use of their so called non-linear optical properties. These properties are generally observed when high light intensities are present and can be used to control and adapt this light. For example it is possible to rapidly switch the light on and off, change the wavelength (colour) of the light and even form a continuum of light from a short pulse using non-linear properties. The aim of this proposal is to develop a new generation of electrophotonic materials by embedding these carbon nanotubes in polymer and chalcogenide glass hosts. Within these CNT-doped hosts waveguides will be formed and their linear and non-linear optical properties studied. We will exploit them to realise highly functional planar lightwave devices .


    Femtosecond Studies of Photonic Devices

    Supervisor:  Professor Jeremy Allam
    Co-Supervisors:   Dr Stephen John Sweeney, Professor Ortwin Hess

    Type of project: Experiment

    Major Aims
  • To apply spectral-temporal techniques to the study of femtosecond pulses interacting with a range of photonic devices and materials

  • To understand physical processes limiting the speed of real-world optical devices

  • To investigate new physical effects in high-intensity, coherent, short-duration pulses propagating in semiconductor optical devices.

  • Techniques Used
  • Ultrafast optical methods using femtosecond titanium-sapphire laser systems.

  • Optical Parametric Oscillator (OPO) and Optical Parametric Amplifier (OPA) light sources.

  • Mixed temporal-spectral methods (e.g. "FROG" - frequency-resolved optical gating)
  • Design of new photonic structures with optimised dynamics.

  • The Student Will Require
    • good hands-on skills with complex experiments

    • some knowledge of lasers, optics and semiconductor physics

    • physical insight to guide the experiments performed

    • willingness to talk and collaborate with theorists

    Project Description

    Spectral-temporal maps of response of laser diode to resonant and non-resonant excitation, showing inversion of relaxation oscillations.
    Femtosecond optical pulses have become an essential tool for the study of photonic materials and devices:

    1. the short duration (<50fs where 1fs =10-15s) allows us to study dynamics of the fundamental processes which limit the switching rate of present photonic devices to the GHz range.
    2. the high instantaneous light intensity allows us to study extreme nonlinear processes, from material modification (e.g. laser writing of optical gratings or waveguides) to fundamental studies of relativistic electron dynamics.
    3. the inherent spectral width allows us to explore the full spectral-temporal response of materials; for example, measuring the chromatic dispersion of light propagating in artificial photonic crystals.
    4. the coherent optical pulses can be shaped in the spectral domain to allow "coherent control" of quantum systems.

    A number of projects are available based on spectral-temporal measurements of femtosecond pulses interacting with different photonic materials and devices. The latter include semiconductor lasers, nonlinear waveguides, and photonic crystals.


    Self-Induced Transparency and Solitons in Semiconductor Microcavities

    Supervisor:  Professor Jeremy Allam
    Co-Supervisors:   Dr. G. Slavcheva, Professor Ortwin Hess

    Type of project: Experiment

    Major Aims
    � To study the interaction of coherent ultrashort light pulses with quantum wells / quantum dots embedded in semiconductor microcavities
    � To establish experimentally the conditions for self-induced transparency (SIT) and soliton formation
    � To investigate possible device applications of SIT solitons

    Techniques Used
    � Propagation of femtosecond laser pulses in semiconductor waveguides
    � Nonlinear optical transmission of semiconductor microcavities in the SIT regime
    � Spatial probing of SIT electron density gratings

    Collaborations
    Prof P Roussignol (Ecole Normale Superieure, Paris, France)

    This is an experimental project linked to the following theoretical project: http://www.ph.surrey.ac.uk/phd/projects?project_id=205

    The Student Will Require
    � good hands-on skills with complex experiments
    � some knowledge of lasers and optics, and/or electronic and optical properties of semiconductors
    � physical insight to guide the experiments performed
    � willingness to talk and collaborate with theorists

    Project Description
    Self-induced transparency (SIT), namely, solitary propagation of an optical pulse in near-resonant media, is one of the most striking and important effects in nonlinear optics. It is a fundamental example of coherent nonlinear light-matter interaction in a discrete-level system, initially discovered in atomic vapours. If the pulse duration is much shorter than the typical material coherence lifetimes, and the pulse area is a multiple of 2π, then reemission of the absorbed radiation in phase with the driving optical field leads to SIT. The nearly lossless ultrashort pulse propagation and the preservation of the pulse shape is extremely attractive for a wide range of applications, such as optical storage and processing of information, optical communication and pulse generation and compression techniques.

    Quantum dots (atomic-like nanostructures in which electrons are localised in all 3 dimensions)are the most promising candidates for observation of SIT due to their long coherence times, and some evidence for SIT has been found in pulse propagation measurements performed on semiconductor quantum dots at low temperature. Theoretical calculations [1] suggest that SIT is enhanced in optical cavities such as semiconductor microcavities, leading to spatio-temporal solitons or "light bullets".

    In this project, the student will look for evidence of SIT in semiconductor waveguides and microcavities, both bul ikand quantum dot. The power threshold for SIT will be determined and compared to theoretical predictions. Techniques for imaging the spatial solitons will be developed, and the prospects of cavity SIT-solitons for novel optoelectronic devices will be assessed.

    Further Reading
    [1] G. Slavcheva, J. M. Arnold and R. W. Ziolkowski, "Ultrafast pulse lossless propagation through a degenerate three-level medium in nonlinear optical waveguides and semiconductor microcavities, Journal of Selected Topics in Quantum Electronics 9, 929 (2003)

    Dr Steven K Clowes

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />EPSRC Advanced Research Fellow

    Short biography:

    1994 BSc in Physics from University of York, UK
    1995 MSc in Surface Science from Loughborough University, UK
    1999 PhD in Experimental Studies of Surface-Adsorbate Interactions and Surface magnetism from University of York, UK
    1999-2001 postdoctoral research associate at Rutgers University NJ, USA
    2001-2007 postdoctoral research associate at Imperial College London, UK
    2007 Laboratory Manager of fabrication facilities for the ATI
    2007-Present EPSRC Advanced Research Fellow at the ATI

    Research Interests:

    I am an experimentalist with an keen interest in all things related to spintronics. Our research into spintronics tends to explore alternative routes to application, which complement the more "traditional" approaches that have been addopted by the community. These include: investigating spin dependent ballistic transport in highly spin-orbit coupled III-V semiconductors, a field sometimes refered to as spin optics, for the development of non-magnetic spin filters; exploring the potential of silicon spintronics for the realisation of atomistic coherent control of spins, for application in quantum computation; the study of the effects of both crystal and structural symmetry on the spin dynamics in semiconductor systems using femto-seconds laser spectroscopy.
    Since joining the photonics group at the ATI, I have become interested in photo-induced effects related to spintronics and their investigation using nano-SQUIDs, a technology that was developed at the ATI in collaboration with NPL.

    Our spintronic lab combines the ATI's ultra-fast laser facility with an 7 Tesla, 1.8 K optical cryostat, which has the capability for low noise electrical measurement. This is complemented by the optical characterisation expertise with the institute. I have an extensive background in device fabrication and I am able to take advantage of the versatile and wide ranging facilities within our cleanroom, which includes a focussed ion beam and e-beam lithography.

    Email: s.clowes@surrey.ac.uk
    Phone: 9827


    Semiconductor Spintronics: Realisation of spin ‘refraction’ devices

    Supervisor:  Dr Steven K Clowes
    Co-Supervisors:   Prof Benedict N Murdin

    Type of project: Experiment

    Major Aims
    Demonstration of spin dependent refraction in semiconductors by the design and development of nanoscale InSb quantum well devices.

    Techniques Used
    You will have access to world-class research laboratories and device fabrication facilities. The project will heavily involve transferable skills in nanoscale device fabrication and high resolution electrical and optical measurements. You will receive comprehensive device fabrication training within state-of-the-art cleanroom facilities

    Including:
    Nanoscale fabrication techniques, including Focused Ion Beam (FIB) writing and electron beam lithography.
    Microfabrication techniques including optical lithography, reactive ion etching, RF sputtered metal deposition and various -surface metrology techniques.
    Electrical characterisation using 7 Tesla superconducting magnet with variable temperature insert and optical access for tunable laser.

    Collaborations
    Imperial College London

    The Student Will Require
    Applicants should hold or expect to obtain a first degree (UK upper second class or equivalent minimum) or a Masters degree in physics, materials, electronic engineering or a related discipline. Candidates from the UK and EU will be eligible for full funding which includes tuition fees and stipend.

    Project Description
    Electron motion across the interface between two different materials behaves in a way analogous to Snell’s Law. Materials or structures can be chosen in such a way that the spin up and down electrons see a different refractive index change (like light polarisation dependence in birefringent materials). Different spins can be made to follow different trajectories providing a method of producing spin polarised currents. The aim of the project will be to demonstrate this theoretical principle and develop this technology.


    Semiconductor Spintronics: Spin transport in quantum well nanowires

    Supervisor:  Dr Steven K Clowes
    Co-Supervisors:   Prof Benedict N Murdin

    Type of project: Experiment

    Major Aims
    Design and development of nanoscale devices to exploit spin dependent electron motion in quantum well nanowires.

    Techniques Used
    You will have access to world-class research laboratories and device fabrication facilities. The project will heavily involve transferable skills in nanoscale device fabrication and high resolution electrical and optical measurements. You will receive comprehensive device fabrication training within state-of-the-art cleanroom facilities

    Including:
    Nanoscale fabrication techniques, including Focused Ion Beam (FIB) writing and electron beam lithography.
    Microfabrication techniques including optical lithography, reactive ion etching, RF sputtered metal deposition and various -surface metrology techniques.
    Electrical characterisation using 7 Tesla superconducting magnet with variable temperature insert and optical access for tunable laser.

    Collaborations
    Imperial College London
    University of Cambridge

    The Student Will Require
    Applicants should hold or expect to obtain a first degree (UK upper second class or equivalent minimum) or a Masters degree in physics, materials, electronic engineering or a related discipline. Candidates from the UK and EU will be eligible for full funding which includes tuition fees and stipend.

    Project Description
    Electrons in magnetic fields will travel if unrestricted along a circular path known as a cyclotron orbit. Recent studies have demonstrated that electron cyclotron motion in two-dimensional nanosystems is spin dependent. It has been proposed that under specific conditions electrons traversing a one dimensional “nanowire” will produce a spin polarised current. The successful applicant will work to demonstrate this effect and develop the technology to produce spin filters/detectors for use by the wider spintronic community.

    Prof Kevin Homewood

    Professor of Semiconductor Optoelectronics

    Short biography:

    Professor Homewood started his research career within the Department of Electrical Engineering at the University of Manchester Institute  of Science and technology (UMIST) obtaining his PhD in 1981. He subsequently spent a period as a Research Fellow at the University of Hull in the Department of Physics. Kevin was appointed Lecturer in Optoelectronics in the Department of Electronic and Electrical Engineering at Surrey in 1984 and was promoted directly to Reader in Semiconductors in 1994 and then to Professor of Semiconductor Optoelectronics in 1999.

    Research Interests:

    At Surrey he has established world-class facilities in electronic and optical characterisation of semiconductors and an active personal research group, which he has led for the past 19 years. He has recently concentrated on developing novel approaches to silicon based optoelectronics and this work is recognised to be world leading in many areas. Kevin is an acknowledged world expert in semiconductor materials and devices and has published more than 180 papers in international scientific journals, including two papers in NATURE that have stimulated international research efforts in semiconducting silicides and silicon optoelectronics.  He was recently awarded a prestigous European Research Council Advanced Investigator Grant  (SILAMPS) of around £ 2,000,000 to develop silicon based lasers and optical amplifiers over the next five years.  He was a cofounder and is a Director of SiLight Technology Ltd.

    Email: k.homewood@surrey.ac.uk
    Phone: 9285


    Development of long wavelength (1.2 - 1.7 micron) silicon based LEDS

    Supervisor:  Prof Kevin Homewood

    Type of project: Experiment

    Project Description
    We have a major well-funded programme on light emitting diodes in silicon. The approach used - dislocation engineering (DE) is seen as major breakthrough in silicon light emission and was reported by us in NATURE stimulating much interest worldwide. Key to this ion implantation based technology is its total compatibility with conventional ULSI processes.

    Applications for this technology include optical data transmission on chip to address the fundamental interconnect bottleneck in microprocessor speed, optical interchip data transfer, cheap transceivers for fibre-to-the-home optical communications and optical sensors.

    The basic technology produces devices that operate at the band edge of silicon (a wavelength of ~1.2 microns). For many applications we are interested in devices that operate over the extended telecommunications range (1.2 - 1.7 micron). We have demonstrated a number of approaches that have given promising preliminary results. This project would involve optimising a number of these routes to efficient light emission.


    Long wavelength Schottky detectors in silicon.

    Supervisor:  Prof Kevin Homewood

    Type of project: Experiment

    Project Description
    We have a major well-funded programme on light emitting diodes in silicon. The approach used - dislocation engineering (DE) - is seen as major breakthrough in silicon light emission and was reported by us in NATURE stimulating much interest worldwide. Key to this ion implantation based technology is its total compatibility with conventional ULSI processes.

    Applications for this technology include optical data transmission on chip to address the fundamental interconnect bottleneck in microprocessor speed, optical interchip data transfer, cheap transceivers for fibre-to-the-home optical communications and optical sensors.

    DE silicon diodes emit below the band gap energy of silicon so the silicon itself cannot be used as a light detector at these wavelengths. Metal/Semiconductor/Metal Schottky detectors offer routes to long wavelength detection. This project will involve the development and evaluation of light detectors with process compatibility with the light emission technology.


    Silicon light emitting diodes in silicon-on-insulator substrates.

    Supervisor:  Prof Kevin Homewood

    Type of project: Experiment

    Project Description
    We have a major well-funded programme on light emitting diodes in silicon. The approach used - dislocation engineering (DE)- is seen as major breakthrough in silicon light emission and was reported by us in NATURE stimulating much interest worldwide. Key to this ion implantation based technology is its total compatibility with conventional ULSI processes.

    Applications for this technology include optical data transmission on chip to address the fundamental interconnect bottleneck in microprocessor speed, optical interchip data transfer, cheap transceivers for fibre-to-the-home optical communications and optical sensors.

    The current technology has been developed in bulk silicon substrates but the microelectronics and photonics industries are moving to silicon-on-insulator (SOI) substrates. This project would involve investigating the transfer of the silicon light technology to an SOI platform.

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />SEPnet Lecturer in the Chemical Synthesis of Functional Nanomaterials

    Short biography:

    Education and Research Experience

    2010-present            University of Surrey (UoS), Guildford, UK. Lecturer/SEPnet Fellow.

     

     

    Chemical Synthesis of Functional Nanomaterials.

     

    2006-2010               Eidgenössische Technische Hochschule (ETH), ZH, CH. Postdoctoral Fellow.

    Advisor: Dr. Prof. François Diederich.

    Efficient Access to Intramolecular Charge-transfer                            Chromophores: New Reactions, Mechanistic Investigations and Structure/Property Relationships.

    2002-2006              University of California, Los Angeles (UCLA), CA, USA. Ph. D., Chemistry. Advisors: Profs. K. N. Houk and M. A. Garcia-Garibay.

    Theoretical Investigations of the Thermochemistry, Structures, and Internal rotation of Conjugated Polyynes.

     

    1997-2002              New York University (NYU), NY, USA. B.Sc., Chemistry.

    Advisor: Prof. David I. Schuster.

    Computational and Experimental Investigations of Steroid-Linked Porphyrin-Fullerene Dyads.

     

    Awards and Fellowships

    2010-present          South East Physics Network (SEPnet) Fellowship (UoS).

    2004-2005              American Chemical Society Organic Division Fellowship sponsored by Organic Reactions, Inc. (UCLA).

    2002                       Isadore Rubiner Award for Excellence in Chemical Research (NYU).

    2002                       Dean’s Undergraduate Research Conference: Protons and Electrons in Motion: Best Speaker in Panel (NYU).

    Research Interests:

    Our research group is interested in the study of supramolecular phenomena using methods from physical organic chemistry with an emphasis on photovoltaics. The strategy involves novel experimental organic synthesis and solution-phase characterization in conjunction with related, and stand-alone, computational projects. Materials processing and analysis will be done in collaborations with the many experts here at the University of Surrey and the Advanced Technology Institute as well as in the South East Physics Network.

    Email: p.d.jarowski@surrey.ac.uk
    Phone: 9862


    Metal Enhanced Intramolecular Charge-transfer: Fundamental Investigation of a New Structural and Electronic Motif in Non-linear Optics.

    Supervisor: 
    Co-Supervisors:   Dr. Malgosia Kaczmarek

    Type of project: Experiment

    Major Aims
    The project aims to establish the working criteria for optimizing the solution-phase non-linear optical molecular properties of intramolecular charge-transfer chromophores (ICT) that double as organic metal ligands as a function of a bound metal, its geometry and its binding position along the ICT backbone. From the results, the design of ordered functional materials will then be developed.

    Techniques Used
    Organic Synthesis, Schlenk Techniques, Column Chromatography, Uv-vis Spectroscopy, all standard organic characterization techniques.

    Collaborations
    Dr. Malgosia Kaczmarek, University of Sauthampton.

    The Student Will Require
    The successful applicant will hold a first degree in chemistry or chemical engineering. The candidate should be able to demonstrate a working knowledge of chemical synthesis either through peer reviewed journal articles or experience performing novel experimental synthetic research. A recommendation letter should be provided directly by the applicant’s recommender, upon request. An interest in photonics and materials chemistry is desirable. Applicants should be able to write quality technical reports in English.

    Project Description
    In general, it is now becoming increasingly recognized that there is a greater advantage in mixing inorganic and organic components to achieve desired materials properties than to operate within the confines of either the organic or inorganic material subclass. This Ph. D. project will address the effectiveness of the use of non-covalent coordination chemistry as a facile means to enhancing the molecular properties of pre-existing organic non-linear optical structural motifs. It will explore the structural, electronic and spectroscopic consequences of metal coordination to organic intramolecular charge-transfer (ICT) ligand systems. This work will explore these fundamental questions by organic and inorganic synthesis, computational chemistry and spectroscopy. Once the fundamentals are established, efforts will be expanded towards dynamic light-up organopolymers, metallomesogens and metallochromophores. Non-linear optical effects in ordered media will be investigated through a partnership with the University of Southampton’s Quantum, Light and Matter Group under the direction of Dr. Malgosia Kaczmarek. The candidate will be expected to spend some time being trained in the use of the facilities at Southampton towards the end of their work at the University of Surrey.

    Further Reading
    (1) Reutenauer, P.; Kivala, M.; Jarowski, P. D.; Boudon, C.; Gisselbrecht, J. –P.; Gross, M.; Diederich, F. "New Strong Organic Super-Acceptors by Cycloaddition of TCNE and TCNQ to Donor-Substituted Cyanoalkynes." Chem. Commun., 2007, 46, 4898-4900. (Citations: 16).

    (2) Jarowski, P. D.; Wu, Y.-L.; Schweizer, W. B.; Diederich, F. "1,2,3-Triazoles as Conjugative p-Linkers in Push-Pull Chromophores: Importance of Substituent Positioning on Intramolecular Charge-Transfer." Org. Lett., 2008, 10, 3347-3350. (Citations: 12).

    (3) Gottschalk, T.; Jarowski, P. D.; Diederich, F. "Reversable Controllable Guest Binding in Precisely Defind Cavities: Selectivity, Induced Fit, and Switching in Novel Resorcin[4]arene-Based Container Molecules." Tetrahedron, 2008, 64, 8307-8317. (Citations: 7).

    (4) Kivala, M.; Boudon, C.; Gisselbrecht, J. –P.; Enko, B.; Seiler, P.; Müller, I. B.; Langer, N.; Jarowski, P. D.; Gescheidt, G.; Diederich, F. “Organic Super-Acceptors with Efficient Intramolecular Charge-Transfer Interactions by [2+2] Cycloadditions of TCNE, TCNQ, and F4-TCNQ to Donor-Substituted Cyanoalkynes.” Chem. Eur. J., 2009, 15, 4111-4123. (Citations: 14).

    (5) Jarowski, P. D.; Wu, Y.-L.; Gisslebrecht, J.-P.; Schweizer, W. B.; Diederich, F. "New Donor-acceptor Chromophores by Formal [2+2] Cycloaddition of Donor-substituted Alkynes to Dicyanovinyl Derivatives." Org. Biomol. Chem., 2009, 7, 1312-1322. (Citations 9)

    (6) Wu, Y.-L.; Jarowski, P. D.; Schweizer, W. B.; Diederich, F. "Mechanistic Investigation of the Formal [2+2] Cycloaddition-Cycloreversion Reaction between 4-(N,N-Dimethylamino)phenylacetylene and Arylated 1,1-Dicyanovinyl Derivatives to Form Intramolecular Charge-Transfer Chromophores." Chem. Eur. J. 2009, 16, 202-211. (Citations 3)

    (7) Wu, Y.-L.; Bureš, F.; Jarowski, P. D.; Schweizer, W. B.; Boudon, C.; Gisselbrecht, J.-P.; Diederich, F. "Proaromaticity: Organic Charge-Transfer Chromophores with Small HOMO-LUMO Gaps." Chem. Eur. J., 2010, 16, 9592-9605.

    (8) Breiten, B.; Wu, Y. -L.; Jarowski, P. D.; Gisselbrecht, J. –P.; Corinne, B.; Griessar, M.; Onitsch, C.; Gescheidt, G.; Schweizer, W. B.; Langer, N.; Lennartze, C.; Diederich, F. "Donor-substituted Octacyano[4]dendralenes: a New Class of Cyano-rich Nonplanar Organic Acceptors." Chem. Sci., 2010, ASAP.


    Probing the Effect of Non-planarity on the Absorptivity and Fluorescence of Aggregation Induced Emitters

    Supervisor: 

    Type of project: Experiment

    The Student Will Require
    The project seeks a chemists or materials chemist. The student will benefit from gained experience in experimental and preparative lab work along with computer simulations. The student should have experience in organic synthesis.

    Project Description
    Aggregation Induced Emission (AIE)1 is a newly identified photophysical phenomenon whereby certain propeller-shaped (non-planar) organic molecules emit absorbed light efficiently only when aggregated in poor solvents. When well solvated (mono-dispersed) the molecules tend to release excitation energy as heat (vibrations and rotations) rather than light. Thus, the phenomenon is likely caused by the nature of the supramolecular structure in the aggregated state, which may be restricting specific energy-dissipating rotational modes at the molecular level.

    This behaviour is in strong contrast to the more typical Aggregation Caused Quenching (ACQ) observed for planar organic molecules. In general, emission quenching, such as ACQ, is an important problem in materials science. The unwanted quenching arises from the strong interaction between molecules in the condensed state. It seems that molecular non-planarity, as found in AIE systems, reduces these interactions, while, at the same time, the rigidity imposed by the medium likely turns-off thermal energy dissipation. Most importantly, however, molecular non-planarity also deleteriously affects chromophoric properties such as absorptivity (uptake of photonic energy) and HOMO-LUMO gap (energy of the emitted light). Both are key factors in the design of fluorescent, semiconductor and photovoltaic devices.

    This project aims to establish the link between the degree of molecular non-planarity and the emission enhancement or quenching in aggregated states. The goal would be to identify geometric and electronic features that optimize fluorescence and minimize intermolecular interactions in the aggregates: How close to planarity can the systems become before quenching begins to dominate? By a convergent and straightforward synthesis, a target set of molecules will be made and studied for their AIE behaviour. The series represents a systematic alteration of certain geometric parameters of a prototypical AIE system. The planarity of these systems can be seamlessly tuned and connected to emissivity. This work will be supported by computational methods and may lead to transient IR measurements to probe molecular rotations following photo-absorption.



    Further Reading
    Hong, Y.; Lama, J. W. Y.; Tang, B. Z., “Aggregation-induced emission: phenomenon, mechanism and applications.” Chem. Commun., 2009, 4332.

    Dr Goran Mashanovich

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Royal Society Research Fellow and Senior Lecturer in Silicon Photonics

    Short biography:

    Goran Mashanovich obtained his Dipl. Ing. and M.Sc. degrees in Electrical Engineering from the University of Belgrade, Serbia, and PhD from the University of Surrey, UK. From 2006, he has been the manager of the Silicon Photonics Group at Surrey, and he was awarded a Royal Society Research Fellowship in 2008. Goran is also a Senior Lecturer at the Department of Electronic Engineering.

    Research Interests:

    Goran's research interests include silicon photonic waveguides, couplers, filters and modulators. He has initiated research in mid-IR group IV photonics recently.

    Email: g.mashanovich@surrey.ac.uk
    Phone: 6123


    Mid-infrared Silicon Photonic Photonic Devices for Sensing and Astronomy

    Supervisor:  Dr Goran Mashanovich
    Co-Supervisors:   Prof Graham T Reed

    Type of project: Experiment

    Major Aims
     To design, fabricated and evaluate waveguides for mid-infrared wavelength range
     To design, fabricate and characterise couplers and filters based on the mid-IR waveguides
     To work on more complex devices that can find application in environmental sensing and astronomy

    Techniques Used
     Optical characterisation of different mid-IR waveguides using fibre coupling (propagation loss, bend loss etc)
     Design of mid-IR photonic circuits using FIMMWAVE/FIMPROP, BeamProp, Comsol, and Silvaco

    Collaborations
    Universities of St Andrews, Leeds, Warwick, Southampton, Singapore

    Project Description
    Mid-infrared silicon photonics is a new research field in the UK, initiated by Dr Mashanovich, a Royal Society Research Fellow. Whilst the current focus of the Si photonics community is the telecom wavelength range, silicon photonic devices at longer wavelengths can have a huge impact in sensing, medical and military applications, as well as free space communications, or astronomy. Silicon is transparent in the 1.2 - 8 micron wavelength range and beyond 24 microns. Therefore, photonic devices based on silicon can be used in environmental and biochemical sensors, for detection of explosives and other hazard materials, for tissue ablation, cancer treatment, missile detection, and free space communications. These devices can be small, low cost and can have significant performance advantages over currently available devices.

    The main challenge is that the most popular platform in the near-infrared wavelength region, that of silicon-on-insulator (SOI), cannot be used in the mid-infrared except in the 2.9 – 3.6 micron region due to high losses of SiO2. Therefore, new materials and waveguide geometries need to be investigated. After successful demonstration of waveguiding in these new structures, more complex devices such as filters, couplers, modulators, detectors etc will be built and characterised, with the ultimate goal of designing compact, low cost environmental sensors and astrophotonics devices.

    Prof Benedict N Murdin

    Professor of Physics,
    Photonics Group Leader,
    Associate Dean (Research and Enterprise) for the Faculty

    Short biography:

    1966 born Rochester NY, USA (British/US dual national)
    1989 BA in Physics from Cambridge University, UK (upgraded to a free MA after a couple of years!)
    1990 MSc in Optoelectronics from Heriot-Watt University, Edinburgh, UK
    1993 PhD in Semiconductor spectroscopy from Heriot-Watt University Edinburgh, UK
    1993 - 1996 European Union Marie Curie fellow at FOM-Rijnhuizen, Utrecht, NL
    1996 - 2002, Lecturer at University of Surrey.
    2002 - 2004, Reader
    2004 - present, Professor of Physics
    2005 - 2007 School Director of Research
    2007 - present Associate Dean (Research and Enterprise)

    Research Interests:

    I am an experimentalist interested in the study of electronic and optical properties of semiconductors and semiconductor nanostructures using high-pressures, magnetic-fields, and linear, nonlinear and time resolved infrared spectroscopy. I am a regular user of the Free-Electron Laser, FELIX, in Holland, and I am the coordinator and spokesperson for UK Condensed Matter Physics users there. I am also a Programme Advisory Committee member for the Dresden laser, FELBE.  I like "applicable physics" rather than really pure or really applied physics, for example I study how quickly and why electron spins lose their memory (applicable to spintronic devices). I chaired the International Conference on Narrow Gap Semiconductors, here in Guildford in 2007.

    Email: b.murdin@surrey.ac.uk
    Phone: 9328


    Quantum Cascades based on silicon

    Supervisor:  Prof Benedict N Murdin

    Type of project: Experiment

    Major Aims
    • To study the transition probability of holes in valence band quantum wells made from silicons-germanium

    • To learn how to control these rates for application to lasers

    Techniques Used
    We shall investigate the transition rates between states in quantum wells using femtosecond light pulses, both in the mid-infrared from the new "ultrafast" laser facility here at Surrey or with the far-infrared FELIX facility in Holland.

    Collaborations
    The project is in collaboration with Universities of Heriot-Watt (Edinburgh), Linz (A), Cambridge, Neuchatel (CH). Industrial collaborators are Thales (Paris), Teraview (Cambridge).

    The Student Will Require
    A good degree in a physics or engineering related subject

    Project Description

    The figure shows the trajectory of an electron falling down the Quantum Cascade in a conduction band device, and holes floating up the staircase in a valence band device.

    Quantum Cascades are a type of semiconductor structure that can be used to produce a new type of laser. In this structure the electrons skip down a staircase staying all the while within one band, unlike in conventional "interband" lasers where electrons jump across the bandgap and recombine with holes to give out the photons. The staircase is designed using the simplest quantum mechanics - the particle-in-a-box problem - and the most demanding crystal growth technology. When one type of semiconductor is grown on top of another, the electron usually prefers to sit in one of them. This means a potential well can be made and if the layers are thin enough a "quantum well" is formed where there are allowed states with forbidden energies between. If wells are stacked very close to each other quantum-mechanical tunneling can occur from one to the next. Putting on an electric field can make the ground state of one well line up with the excited state of the next, producing the stair-case. Quantum Cascade Lasers were first produced ten years ago using the semiconductor InP, and recently GaAs, which is much cheaper, but still several thousand Euro a piece! The ultimate would be to produce a QCL from silicon, which could make it affordable for many applications such as environmental pollution monitoring etc.

    We are already collaborating with a large EU consortium to produce Quantum Cascade Lasers from silicon. These devices use holes in the valence band rather than electrons, but the principle is just the same. The main difference is the variety of the set of allowed states because the valence band is actually three different bands mixed together. The aim of this project is to observe the transitions of holes between excited and ground states and measure the transition time. By looking at the change in time with well width, alloy composition etc we hope to learn how to control it, and hence help to produce working lasers.


    Spintronic devices with narrow gap semiconductors

    Supervisor:  Prof Benedict N Murdin
    Co-Supervisors:   Professor Jeremy Allam

    Type of project: Experiment

    Major Aims
    • To study the lifetime of spin polarised electrons in semiconductors with small bandgap

    • To observe spin-polarised currents in the same materials

    Techniques Used
    • Spin polarisations in semiconductors will be generated using circularly polarised light pulses, either from the new "ultrafast" laser facility here at Surrey or with the FELIX facility in Holland

    • The lifetimes will be measured as a function of temperature, pressure and magnetic field

    • Spin filter devices will be made using the nanofabrication clean room facility in the Institute, and transport of spins through the devices will be measured with high magnetic field experiments.

    Collaborations
    The project is in collaboration with Imperial College London, Heriot-Watt University, The University of Regensburg, and the FELIX facility in Utrecht.

    The Student Will Require
    A good degree in a physics or engineering related subject

    Project Description

    SEM image of a 500nm QW wire made by Dr Steve Clowes using a Toshiba-Raith ebeam system at QinetiQ Ltd, using narrow gap semiconductors
    The spin of electrons and holes in solid state systems is an intensively studied quantum mechanical property showing a large variety of interesting physical phenomena. Lately, there is much interest in the use of the spin of carriers in semiconductor heterostructures together with their charge to realize novel device concepts like spintronics and quantum computing. Spintronic transistors have been predicted to be easily reprogrammable, to be much faster and to require much less energy for switching.

    Almost all the studies to date have focussed on silicon and gallium arsenide, the two most important semiconductors in modern technology. However semiconductors with smaller bandgap (e.g. InSb and InAs) have a much higher intrinsic conductivity and electons can be moved a given distance much more quickly. This means that if the spins are all made to stand upright on entering the semiconductor, fewer will be scattered and a greater proportion will remain standing by the time they are collected at the other end of the device. Additionally, spintronic transistor devices need some way of manipulating spin, i.e. to flip them up-side-down and shut off the device, and the prime candidate (called the Rashba effect) is predicted to be larger in strength in these materials.

    The project is to measure the lifetime of spins in narrow bandgap semiconductors in order to understand what causes them to scatter and randomise. Until we can reliably create spins electronically we shall create them with circularly polarised light (photons that spin!). With the results we shall then be able to engineer better materials. We shall measure the magnitude of spin-currents that can be induced, and also the size of the Rashba effect in these materials.

    The most adventurous part of the project will be in collaboration with Dr Steve Clowes, and will involve producing real devices. We shall make spin filter devices based on principles of "spin-orbit coupling", whereby electrons can be polarised without the use of magnets. If we can demonstrate injection and detection of polarised electrons using special combinations of non-magnetic materials, which are much easier to produce, this will be a great leap forwards
    in technology.

    For further reading about spintronics see Scientific American:

    Online Reference
    http://www.sciam.com/article.cfm?articleID=0007A735-759A-1CDD-B4A8809EC588EEDF&pageNumber=1&catID=2


    T-ray spectroscopy of handed molecules

    Supervisor:  Prof Benedict N Murdin

    Type of project: Experiment

    Major Aims
    • To devolop a system capable of recognising the difference between chiral (left- and right-handed) molecules, using T-rays (the THz frequency or far-infrared region of the spectrum)

    • To use the system to observe known simple enantiomers and then to research the utility for larger molecules of pharmaceutical interest

    Techniques Used
    • You will use the state-of-the-art ultra-short pulsed laser system in the ATI to shock a semiconductor, that will react by producing (harmless) T-rays

    • You will then develop a new type of spectrometer that can convert the polarisation of the T-rays so that it becomes circular, and hence sensitive to cirality (handedness) in molecules

    Source of Expertise
    I have a long experience in working with T-rays and spectroscopy of semiconductors with this type of light radiation. Recently I have become interested in devices that use spin polarised electrons, and such polarisations are chiral just like the molecular enantiomers. I would like to develop this interest into chemical spectroscopy.

    The Student Will Require
    A good degree in a physics or engineering related subject

    Project Description

    Glucose (like other sugars) comes in two mirror-image shapes, or "enantiomers", labelled L and D (sometimes S and R instead). Usually only one type occurs in nature (D for glucose).
    Light is normally thought of as a plane-polarised transverse wave, but in the quantum picture it is made up of equal numbers of photons with spin +1 and -1. The photons can be separated with some simple optical tricks, making a beam whose electric field makes a helical path around the axis of propagation either to the right or left, called circular polarisation. The beam therefore has a handedness, and is sensitive to handedness in the subtances it passes through.

    The study of optical activity is of interest for the study of low symmetry crystals, molecules and other systems. There are various different types of optical activity. Linear birefringence is the phenomenon of a difference in the refractive index of a material measured for two orthogonal linear polarisations, and circular dichroism (or birefringence) refers to differences absorption coefficient (or refractive index) for opposite circular polarisations. Cicular dichroism is currently of interest to biochemists for its application in identification and isolation of pharmaceutical enantiomers, where it is important to isolate the left from the right handed kinds and study the effects of each seperately. The classic example is thalidomide, which in one form is a very potent and side-effect-free morning-sickness drug, but in the other form causes infant mutations. Other examples include limonen, which in one form smells of lemons and in the other smells of oranges. The reason for the different chemistry is that the natural molecules in your body are normally purely one enantiomer so its reaction to synthetic compounds is very chirally specific.

    Spectroscopic techniques for analysis of optical activity rely on the use of birefringent crystals that convert plane polarised light into circular polarised light. I propose that you should build a new type of spectrometer that enables optical activity spectroscopy without birefringent crystals, and is therefore applicable to the T-ray region of the electromagnetic spectrum where suitable birefringent crystals are almost impossible to find, but where important information on chemical identification can be found.

    Prof Graham T Reed

    http://personal.ee.surrey.ac.uk/Personal/G.Reed/graham 2b.jpg

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Professor of Optoelectronics, Head of Department of Electronic Engineering

    Short biography:

    Graham Reed obtained his first degree and PhD in 1983 and 1987 respectively. After working for 2 years at ERA Technology Ltd, in 1989 he joined the University of Surrey with the aim of establishing a research activity in guided wave optoelectronics, and now leads an internationally recognised group. He is responsible for initiating a new research field in the UK on Silicon Integrated Optical Circuits, and his group have produced a series of leading technical advances in the field worldwide, notably in optical modulators, grating couplers, and optical sensing applications. A testament to the originality and potential of the silicon work, is that Bookham Technology Plc adopted it as their core business. Graham was appointed as a Professor of Optoelectronics in April 2001.

    Research Interests:

    Graham's research interests include all aspects of silicon photonics, including optical modulators, couplers, AWGs, ring resonators, and Bragg gratings. He also has an active interest in optical fibre sensing, particularly for strain sensing and crack detection in composite materials.

    Email: g.reed@surrey.ac.uk
    Phone: 9122


    High Speed Optical Modulators in Silicon

    Supervisor:  Prof Graham T Reed
    Co-Supervisors:   Dr Goran Mashanovich

    Type of project: Experiment

    Major Aims
    . To achieve 40 Gb/s optical modulation in silicon
    . To investigate different modulator structures in order to
    obtain low power and high extinction ratio
    . To design drivers for the modulator and participate in developing photonic/electronic integration strategies

    Techniques Used
    . Optical characterisation of the modulator (using setups shown in Figure 1)
    . Electrical characterisation of the modulator using a 65 GHz setup in the Silicon Photonics Labs
    . Design of photonic circuits using FIMMWAVE/FIMPROP, BeamProp, Comsol, Silvaco, Labview, Ledit and other commercial software packages

    Collaborations
    LETI, IMEC, IHP and Universities of St Andrews, Leeds, Warwick and Southampton.

    Project Description
    One of the most challenging areas in the field of silicon photonics, which has been extremely buoyant in the last 5 years, is realisation of low power, large modulation depth, high speed optical modulators. As silicon is centro-symmetric crystal, electrooptic effect present in other materials that are usually used for modulators, such as LiNbO3 or III-V compounds, is absent. Our group suggested carrier depletion as a modulation mechanism in silicon and we have achieved modulation of 10 Gb/s. The main aim of this project is to achieve higher modulation speeds (target 40 Gb/s) with improved modulation depth and reduced power consumption. The integration of the modulator with drivers and electronics on the same chip will also be investigated.
    Novel modulator structures based on Mach-Zehnder Interferometer and ring resonator will be investigated in this project. Interaction with our partners in the UK and EU is crucial for the success of the project and it is expected that the successful candidate will travel to those institutions to discuss design, fabrication or evaluation of devices.

    This project is a part of £5 Million EPSRC grant ‘UK Silicon Photonics’.
    Further information can be obtained by logging on to
    www.uksiliconphotonics.co.uk


    Optical Filters for Integrated Photonics Circuits in Silicon

    Supervisor:  Prof Graham T Reed
    Co-Supervisors:   Dr Goran Mashanovich

    Type of project: Experiment

    Major Aims
    . To design, fabricate and evaluate ring/racetrack resonator structures
    . To investigate fabrication tolerances and temperature dependence of devices
    . To fabricate Bragg gratings by ion implantation
    . To work on novel filter designs

    Techniques Used
    . Optical characterisation of the filters using both free space and fibre coupling
    . Design of filters using FIMMWAVE/FIMMPROP, BeamProp, Comsol, Silvaco, King, LEdit and other commercial software packages


    Collaborations
    Intel, QinetiQ, LETI, IMEC and University of St Andrews

    Project Description
    One of the building blocks of an integrated silicon photonic circuit is an optical filter. In this project, several types of optical filters will be investigated: ring/racetrack resonators, Bragg gratings, echelle gratings etc.

    The project will involve extensive simulations, design of novel filters and their characterisation at Surrey. Fabrication will be carried out at IMEC and LETI. This project is a part of a £5 Million EPSRC grant ‘UK Silicon Photonics’.

    Further information can be obtained by logging onto
    www.uksiliconphotonics.co.uk

    Dr Stephen John Sweeney

     

     

     

    Research Interests:

    Stephen's primary research interests lie in the area of semiconductor laser physics with a particular onus on optimising laser performance. He has produced >150 journal papers and conference proceedings in this area including several invited papers. Stephen has recently expanded his interests into photonic sensors based on both III-V and Si technologies. Recent topics include:



    Information about currently available PhD projects can be found here

     

     

     

     

    Email: s.sweeney@surrey.ac.uk
    Phone: 9406


    A radical approach to temperature insensitive photonic materials and devices

    Supervisor:  Dr Stephen John Sweeney

    Type of project: Experiment and Theory

    Major Aims
    One of principal problems with all modern electronic and optoelectronic/photonic devices is the fact that the semiconductors on which they are based change their properties as the ambient temperature varies. For exmaple, as an LED or laser heats-up, its band gap changes meaning that the emission wavelength changes. This is particularly problematic if one wishes to make a stable high efficiency light source, or for example, sending information down an optical fibre at a particular wavelength. In electronics, properties such as the effective mass are linked to the band gap and changes in mass change the transport of electrons through the material (i.e. change its resistivity - important in electronics). This means that temperature stabilisation electronic are often required to maintain a constant temperature. Such systems typically demand 10x more energy than the devices themselves. There are therefore considerable energy savings to be made by producing temperature insensitive semiconductors, with consequent positive environmental and economic benefits.

    The aims of this project are to take a radical look at alloy physics and the extent to which mixed semiconductors encompassing the II-VIs, III-Vs and II-IVs may be used to produce semidconductors with good photonic and electronic properties that are also temperature stable. The project will principally be theoretical, but as the project progresses the aim will be to produce some real material and devices.

    Techniques Used
    The project will largely involve simulating the properties of semiconductors computatinally using both bespoke and commercial software. The outputs will be:

    - Models of the semiconductor bandstructure

    - Detemination of the temperature dependence of key properties, e.g. band gap, effective mass, band offsets

    - Prediction of device properties based upon these materials

    Collaborations
    This project will involve collaborations with other universities and companies based in Europe and North America

    The Student Will Require
    Potential students should have a strong interest in modelling the physics of semiconductors whilst keeping in mind device applications


    Broad Band Light Sources for Optical Coherence Tomography

    Supervisor:  Dr Stephen John Sweeney

    Type of project: Experiment and Theory

    Major Aims
    The aim of this project is to investigate and develop high brightness optical sources for applications in Optical Coherence Tomography. The project will consider approaches based on quantum well and quantum dot based devices (semiconductor lasers and superluminescent LEDs) using a combination of experimental and theoretical approaches

    Techniques Used
    Experimental:

    - temperature and pressure depdendence of steady-state optical and electronic properties

    - set-up of a simple OCT interferometer

    Theoretical:

    - active region design and optimisation

    - modelling of carrier recombination in lasers, amplified spontaneous emission and non-equilibrium conditions in semiconductor lasers and LEDs


    Source of Expertise
    This project will utilise the state-of-the-art photonic characterisaiton labs in the Advanced Technology Institute. It will also be highly collaborative, working with semiconductor producers in the USA

    Collaborations
    Arizona State University, USA

    The Student Will Require
    A strong interest in photonics and its application in medicine and diagnostics

    Online Reference
    http://en.wikipedia.org/wiki/Optical_coherence_tomography


    Compound semiconductors for next generation electronic and photonic devices

    Supervisor:  Dr Stephen John Sweeney

    Type of project: Experiment

    Major Aims
    The aim of this project is to investigate new semiconductor materials for applications in photonics and electronics. The core theme of this work is understand and exploit the properties of III-V alloys containing group V elements such as Nitrogen and Bismuth. Whilst these are quite dissimilar atoms, they can both have remarkable effects on III-V semiconductors giving rise to the possibility of efficient lasers and solar cells, optical computing, spintronics and THz applications.

    Collaborations
    University of Marburg, Germany
    Arizona State University, USA
    University of British Columbia, Canada
    University of Michigan, USA

    Project Description

    Groups III-V of the periodic table are key to modern photonic and electronic devices.
    In this project we will investigate III-V semiconductors both in terms of their fundamental physical properties and their application in real devices such as lasers and solar cells. Experimental activities will focus on developing novel spectroscopic techniques to determine the nature of the band structure of these materials; such techniques include photocurrent spectroscopy, photo-, and electro-luminescence and modulation techniques, eg. modulation of the structure through external fields etc. Part of this study will also utilise the unique high pressure and low temperature facilities at Surrey which offer a useful way of manipulating, for example, the band structure and physical properties of the semiconductors.



    The second aspect of this project will be to characterise fully-functional devices based on these materials, eg. lasers, light-emitting diodes or solar cells, as they become available. The knowledge gained from the spectroscopic studies with be used to help develop optimum devices where we will be interested in maximising parameters such as efficiency or producing temperature insensitive operation.

    The project will be backed up with strong theory both at Surrey and other leading international groups. Furthermore, the experimental work will be highly collaborative, involving academic and commercial groups in the USA, Europe and Japan.



    Silicon compatible III-V lasers for optical computing and optical interconnects

    Supervisor:  Dr Stephen John Sweeney

    Type of project: Experiment

    Major Aims
    The aim of this project is to investigate a new optoelectonic materials system that is directly compatible with silicon electronics. The eventual aim of the project is to produce lasers on silicon which are compatible with standard CMOS electronics technology and which will enable fast optical buses within computers. This would revolutionise computing by reducing power consumption and increasing data transmission rates.

    In this project you will investigate GaAsPN-based lasers which may be grown directly on silicon. The project will focus on the carrier recombination processes which limit the efficiency of the lasers and their maximum operating temperature.

    Techniques Used
    High pressure and low temperature measurements will be used to:

    * Determine the band structure and band offsets of GaAsPN/GaP using photocurrent and electroluminesce measurements on LEDs and lasers

    * Investigate the dominant carrier recombination processes in this material and the extent to which they limit device efficiency and maximum operating temperature.

    * Determine the modulation properties of GaAsPN lasers

    Collaborations
    University of Marburg, Germany

    Ion Beam Centre

    http://www.ee.surrey.ac.uk/ibc

    Prof Karen J Kirkby

    Associate Dean for Research and Enterprise

    Short biography:

    Karen Kirkby (formerly Reeson) joined Surrey in 1984 after completing a PhD on the optical properties of ores at the Natural History Musem in London. In 1989 she spent some time at AT& T Bell Labs, USA and returned to a lecturship and was later promoted to Senior Lecturer (1995) and then to Reader (2002).

    She is actively involved with the Surrey Ion Beam Centre being a grant holder and heads the UK research Network on Biomedical applications of ion beams.

    She has published over 120 jornal and 70 conference publications (some invited) and has also written for popular science magazines such as Physics World and New Scientist. She has received 2 prizes for research achievements.

    Apart from AT&T she has spent time at the Universities of Paris, uppsala and Oxford and The Natural History Museum in London where she was a visiting Fellow.

    Research Interests:

    KJK has been actively involved in ion beam synthesis (IBS)for the past 20 years she was part of the successfull UK team that developed SIMOX (an SOI substrate) which is now widely used commercially. She used this expertise to develop IBS of silicides and in 1997 published results in Nature of a silicon based LED. She is now actively involved in using IBS to fabricate silicon based light emitting devices and to fabricate novel superconductors.

    KJK heads a UK Network on biomedical applications of ion beams and is a grant holder on a MCRTN Cellion. Her research interests lie in the study of how radiation interacts with cells and tissue, trace element analysis in biomedical materials, and novel micro and nanostructures created by p-beam writing.

    KJK is also working on how dopants behave in ultra shallow devices, looking at the effects of preamorphisation and Si and SOI substrates. This research is in collaboration with Applied Materials

    Email: k.kirkby@surrey.ac.uk
    Phone: 9846


    Trace element analysis in cells and tissues

    Supervisor:  Prof Karen J Kirkby
    Co-Supervisors:   Kirkby N, Prof Roger P Webb

    Type of project: Experiment

    Major Aims
    Trace element mapping in cells and tissue using the scanning proton microbeam. Analysis will initially be undertaken on the micron scale but will subsequently use the new nanobeam to analyse sub micron structures. The project will involve collaboration with some of premier research establishments within the UK

    Techniques Used
    Ion Beam Analysis (PIXE, RBS, NRA, STIM)

    Collaborations
    EPSRC Network on Biomedical applications of MeV Ion beams

    EU FP6 MCRTN Cellion

    The Student Will Require
    Physics, Engineering, Biological Sciences, Chemistry

    Project Description
    Trace element mapping in technologically or medically important samples. Looking at how trace elements move in cells and tissues and how they are distributed. The project will be with leading centres in the UK and will seek to take the state of the art from vaccuum studies to in medium living cell and tissue studies. It will also use the new nanobeam to probe structures which have previously been too small to analyse.

    Online Reference
    http://almaren.ee.surrey.ac.uk/biomed/


    Tuning emission from nanoclusters

    Supervisor:  Prof Karen J Kirkby
    Co-Supervisors:   Prof Roger P Webb

    Type of project: Experiment

    Major Aims
    To tune the wavelength of light emitted from silicon nanocrystals embedded in SiO2 using co-implants

    Techniques Used
    ion implantation
    PECVD growth
    ion beam beam analysis
    PL, EL, DLTS

    Collaborations
    University of Southampton
    University of Sheffield Hallam
    University of Oxford

    The Student Will Require
    Physics, Engineering, Materials science

    Project Description
    To fabricate silicon nanocrystals in SiO2 using either ion implantation or PECVD growth. To then modify the wavelength of the light emitted by either synthesising compound nanocrystals or putting the wavelength tuning ion in close proximity to the nanocrystal. Fabrication of test devices and arrays


    Ultra shallow junction formation in Si and SOI

    Supervisor:  Prof Karen J Kirkby
    Co-Supervisors:   Prof Nick EB Cowern, Prof Roger P Webb

    Type of project: Experiment

    Major Aims
    To understand the way in which Si and SOI which have been pre-amorphised prior to implantation behave with different dopant and impurity species and the way in which this influence the formation and regrowth of the amorphous silicon. Study of how the dopants activate and de-activate using different annealing treatments.

    Techniques Used
    ion implantation
    ion beam analysis
    Hall effect, 4 point probe
    annealing

    Collaborations
    Applied Materials UK
    Applied Materials Santa Clara

    The Student Will Require
    Physics, Engineering, Chemistry

    Project Description
    For ULSi devices SOI and Si substrates are often pre-amorphised prior to dopant implantation. This makes use of Si, Ge or Sn implants. In this study different elements are used to pre-amorphise and then dopant implants are implanted and the regrowth of the amorphous layers studied. Different rapid thermal annealing treatments are used and the dopant activation and deactivation studied.

    Online Reference
    http://www.ee.surrey.ac.uk/ibc/index.php?target=6:16

    Prof Roger P Webb

    Professor of Ion Beam Physics
    Director of Ion Beam Centre

    Short biography: Roger joined the Department in 1983 as a Research Fellow with the SRC (as it was then - interesting how the EPSRC has gained letters over the years) Surrey Ion Beam Centre. He was employed to look after the computing facilities associated with the research group - a single pdp11, about half of the computer "power" in the department in those days.

    Before this he had spent 3 years as a post doc at the Naval Postgraduate School in Monterey California, making Molecular Dynamics Studies and Computer Animations, which is still the main area of his research activities. He did his PhD work in the Electronic & Electrical Engineering Department of the University of Salford, on the Mathematical Modelling of Atomic Collisions in Solids.

    He was made a Lecturer in the Department in 1986, promoted to Senior Lecturer in 1993 and then to Reader in 1997, reaching the dizzy geights of Professor of Ion Beam Physics in 2002. He is the current head of the Ion Beam Centre.

    Research Interests: Main area of research is the interaction of energetic ion beams with solids.

    Current research activities include the use of Molecular Dynamics Simulations to predict the behaviour of cluster and molecular impacts on surfaces. As well as the use of more simple Binary Collisions simulations to predict the effects of energetic particle solid interactions, in particular ion implantation profiles in crystalline solids.Cluster and molecular impacts include fullerene impact induced desorption.

    See my personal pages for links to some of the results from these research programmes.

    Other areas of interest are in automation and control of ion beam analysis equipment. This includes software to automate the collection of data from standard analyses using RBS, PIXE, PIGE, NRA and ERD.He must also take some responsibility for the windows interface to the Data Furnace for the automated and rapid analysis of experimental ion scattering data.

    Email: r.webb@surrey.ac.uk
    Phone: 9830


    Atomistic simulation of nano-device fabrication processes

    Supervisor:  Prof Roger P Webb
    Co-Supervisors:   Prof Karen J Kirkby, Professor Brian Sealy

    Type of project: Experiment and Theory

    Major Aims
    Electronics technology is entering a new era as device dimensions approach the nanometer scale and novel device architectures are being considered for future devices. Modelling is often the only available way to start exploring how to fabricate such devices. The project aims to understand, model and simulate atomic-scale processes occurring in device structures during fabrication. The project offers great opportunities to interact with scientists in the semiconductor industry and leading European research institutes.

    Techniques Used
    Modelling and simulation of atomic interactions involved in ion implantation, diffusion and clustering processes in solids, using atomistic and continuum methods. Interaction / involvement with an enthusiastic group of PhD colleagues working on ion implantation, defect engineering, differential Hall profiling, and laser annealing.

    Collaborations
    Applied Materials (Santa Clara USA and Horsham UK)
    Philips Research (Leuven, Belgium)
    ST Microelectronics (Grenoble, France)
    Universidad de Valladolid, Spain

    The Student Will Require
    Physics, Engineering, Chemistry

    Project Description
    For ULSi devices SOI and Si substrates are often pre-amorphised prior to dopant implantation. This makes use of Si, Ge or Sn implants. In this study different elements are used to pre-amorphise and then dopant implants are implanted and the regrowth of the amorphous layers studied. Different rapid thermal annealing treatments are used and the dopant activation and deactivation studied.

    Online Reference
    http://www.ee.surrey.ac.uk/ibc/index.php?target=6:16


    Computer Simulation of Cluster/Molecule Surface Impacts

    Supervisor:  Prof Roger P Webb
    Co-Supervisors:   Prof Karen J Kirkby

    Type of project: Theory

    Major Aims
    Understand the Mechanism of Cluster Impact Induced Desorption at low impact energy

    Calculate the damage cross sections and understand the damage mechanisms involved in energetic cluster surface impacts

    Exploit this understanding to improve the performance of the "Cluster SIMS" analysis technique particularly for analysis of large molecular species


    Techniques Used
    Molecular Dynamics computer simulations
    Comparison with Cluster SIMS results.

    Collaborations
    UMIST
    Penn State University

    The Student Will Require
    Ability to program, language not an issue, just some basic experience in programming is essential

    Project Description

    fullerene impact on graphite surface with monolayer of benzene adsorbed. The carbon surface "aids" the desorption process
    Secondary Ion Mass Spectrometry is a technique that has been used very successfuly in materials characterisation for a number of years now. In the last few years a new development in the use of polyatomic ion beams has demonstrated a massively increased yield of intact molecules from organic surfaces.
    This project will seek to explain the mechanisms behind this increased yield and help experimentalists at Penn State Manchester Universities optomize their experiemtal proceedures.

    Online Reference
    http://www.ee.surrey.ac.uk/ibc/index:php?target=6:29


    Dopant profile engineering for NanoCMOS devices

    Supervisor:  Prof Roger P Webb
    Co-Supervisors:   Prof Karen J Kirkby, Professor Brian Sealy

    Type of project: Experiment

    Major Aims
    To find ways to create very high concentrations of electrically active dopants in specific regions of CMOS devices, needed for ultra-fast, low-power CMOS technology (45 nanometer and beyond). This challenging project involves both basic physics and engineering, as it aims to build knowledge and understanding of atomic-scale processes in Si, SiGe and Ge, and apply the results to an ultimate engineering problem at the nanometer scale. The project gives excellent opportunities for an outstanding student to interact with researchers at a range of international companies and institutes.

    Techniques Used
    Ion implantation, defect engineering, differential Hall profiling, four-point-probe measurements, rapid thermal annealing, and laser annealing (both at Surrey and at an external partner institution). Modelling and simulation of dopant diffusion and atomic interactions, in collaboration with PhD colleagues working on modelling.

    Collaborations
    Applied Materials (Santa Clara, USA; Horsham, UK)
    Philips Research (Leuven, Belgium)
    ST Microelectronics (Grenoble, Fr.)
    Fraunhofer Institute (Erlangen, Germany)
    CNRS Institute (Toulouse, France)

    The Student Will Require
    Physics, Engineering, or Chemistry

    Online Reference
    http://www.ee.surrey.ac.uk/ibc/index.php?target=6:16


    Modelling of Proton Therapy

    Supervisor:  Prof Roger P Webb
    Co-Supervisors:   N F Kirkby, N G Burnet, Prof Karen J Kirkby

    Type of project: Experiment and Theory

    Major Aims
    To model the effects of proton (and heavier ions) in biological systems including cells, tissue and the body. The impact of this research will be in aiding the treatment of cancer using particle beam therapy. The research couples into two recently approved Basic Technology grants (£13M in total) to investigate the next generation of particle therapy machines.

    Techniques Used
    computer simulation, particle solid interactions, multiscale modelling

    Source of Expertise
    medical physicists and clinicians in Cambridge, Oxford and Surrey
    simulation at Surrey

    Collaborations
    Addenbrooke's Hospital, Dept Oncology, University of Cambridge
    UK Research Network on Biomedical Applications of Ion Beams
    EU MCRTN CELLION

    The Student Will Require
    programming experience, any language
    Physics, Maths, Engineering

    Project Description
    After surgery raditherapy is the most effective means of curing cancer. This project seeks to make it even more effective by adding proton and light ion therapy to the options available to the clinician when planning therapy. The project involves working with medical physicists and clinicians to develop useful models for the prediction of the effects of energetic ions interacting with biological systems.

    Online Reference
    http://almaren.ee.surrey.ac.uk/biomed/

    Nano-Electronics Centre

    http://www.ati.surrey.ac.uk/lae

    Dr David Carey

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Senior Lecturer in Electronic Engineering

    Short biography:

    Research Interests:

    My research interests are mainly focussed in

    1. Nanotechnology and nanomaterials in particular carbon based marterials (nanotubes, graphene and DLC). I was the Guest Editor of the Journal of Material Science:Materials in Electronics   (June 2006) for a Special Issue on carbon based electronics. 
    2. the applications of low dimensional materials as field emitters
    3. the structure, transport and electronic properties of nanomaterials
    4. Commerical applications of nanomaterials. Nanotechnology and Society.

    PhD Research Positions 

    For a PhD position you will normally require a good Honours degree or MSc in Electronic Engineering, Physics or Materials. See PhD project list here for more information

    Email: david.carey@surrey.ac.uk
    Phone: 6089


    Nanoelectronic Devices: High Power Electron Sources

    Supervisor:  Dr David Carey
    Co-Supervisors:   Prof. S. Ravi P. Silva

    Type of project: Experiment

    Major Aims
    CNT technology for Electron Sources: Carbon nanotubes are excellent sources of electrons. Their long thin shape means that only low applied electric fields are needed to extract the electrons. We aim to be able to produce high current density from nanotubes for higher power applications.

    Techniques Used
    1. Growth of carbon nanotubes in selected device geometries

    2. Deposition, optical and electrical characterisation of different types of carbon.

    3. Field emission characterisation of Electron Sources.

    The Student Will Require
    First class degree in electronic engineering, physics or materials

    In addition the student should have an interest in electronic devices and how they can be optimised by changing the growth conditions.

    Further Reading
    See also



    Interpretation of enhancement factor in nonplanar field emitters, R. C. Smith, R. D. Forrest, J. D. Carey, W. K. Hsu and S. R. P. Silva, Appl. Phys. Lett. 87, 013111 (2005).


    Online Reference
    http://www.ati.surrey.ac.uk/NEC/


    Nanostructured Materials by Laser processing

    Supervisor:  Dr David Carey
    Co-Supervisors:   Prof. S. Ravi P. Silva

    Type of project: Experiment

    Major Aims
    The aims of this project are to grow, characterise a range of important electronic materials using high power pulsed laser ablation.

    Materials include nanoporous carbon, metal containing DLC and porous films as well as laser processing of other materials is also possible.

    Techniques Used
    Pulsed laser ablation using an Excimer laser.

    Scanning electron microscopy

    Atomic force microscopy

    Electrical measurements (current-voltage)

    The Student Will Require
    First class degree in electronic engineering, physics or materials

    Further Reading
    See

    Pulsed-laser-induced nanoscale island formation in thin metal-on-oxide films, S.J. Henley, J.D. Carey and S.R.P. Silva, Phys. Rev. B 72, 195408 (2005).


    Excimer laser nanostructuring of nickel thin films for the catalytic growth of carbon nanotubes, S. J. Henley, C. H. P. Poa, A. A. D. T Adikaari, C. E. Giusca, J. D. Carey and S. R. P. Silva, Appl. Phys. Lett. 84, 4035 (2004).


    Nanotechnology in Action: Carbon Nanotube Composites

    Supervisor:  Dr David Carey

    Type of project: Experiment

    Major Aims
    The project aims to study the electronic properties of carbon nanotube (CNT) composite materials. By adding small amount of CNTs to other polymer materials significant changes in the electrical characteristics of the materials can occur. This project will combine some electrical characterisation with structural examination of nanotube polymer composites.

    Techniques Used
    Electrical measurements as a function of nanotube mass fraction.

    Scanning electron microscopy for structural analysis

    Collaborations
    Trinity College Dublin (Ireland). It may be possible to spend some time in Dublin.

    The Student Will Require
    First class degree in electronic engineering, physics or materials.

    In addition the student should have an interest in nanotechnology and the electronic properties of carbon nanotubes.

    Further Reading
    For more information see


    Charge transport effects in field emission from carbon-nanotube polymer composites, R.C. Smith, J.D. Carey, R.J. Murphy, W.J. Blau, J.N. Coleman and S.R.P. Silva, Appl. Phys. Lett. 87, 263105 (2005).



    Studies of Graphene

    Supervisor:  Dr David Carey

    Type of project: Theory

    Major Aims
    This project will use ab initio method to examine the electronic properties of graphene and graphene related materials such as nanoribbons. Of particular interest is the interaction of the grapehne layer with molecular adsorption.

    For further information of hydrogen on graphene see
    http://link.aps.org/doi/10.1103/PhysRevB.75.245413

    For more information on graphene please see the review articles
    http://onnes.ph.man.ac.uk/nano/News/PhysicsToday_2006.pdf
    and http://onnes.ph.man.ac.uk/nano/Publications/Naturemat_2007Review.pdf

    Techniques Used
    Ab initio methods using existing software.


    Transport in Electron Systems

    Supervisor:  Dr David Carey

    Type of project: Theory

    Major Aims
    Using Matlab or another programming system, this project will examine the factors that control electron transport in low dimensional systems. In particular the study of materials properties and device architecture will be examined. Of particaulr interest at the moment are devices based on graphene. Electron tunnelling in this material behaves differently from other materials and we wish to explore that here.

    Techniques Used
    Matlab, programming should be strong.

    Dr Richard Curry

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Senior Lecturer

    Short biography:

    1993 - 1996 BSc in Theoretical Physics (1st class Hons)  Queen Mary University of London (QMUL)

    1996 -1999 PhD 'Luminescence characterisation of AlQ and ErQ', QMUL

    1999 - 2001 EPSRC Research Associate, QMUL. 

    2001 - 2004 Research Fellow Optoelectronics Research Centre (ORC), University of Southampton

    2003 co-founded ChG Southampton Ltd

    2004 - present Lecturer/Senior Lecturer, Advanced Technology Institute (ATI), University of Surrey.

    Research Interests:

    My research interests are generally based around the study and development of organic and hybrid organic-inorganic and chalcogenide material systems for applications in optical and electronic devices. In particular my research has included the development and study of organometallic and organolanthanide complexes for applications in near-infrared optical devices. I also study hybrid organic-quantum dots systems with an emphasis on energy transfer processes and their use in near infrared emitting and photovoltaic devices. Related to this work is a continuing research programme studying C60 fullerite nanorods for optoelectronic applications. This work has been successfully applied to photovoltaics and light emitting devices including those in the infra-red. I also carry research into metal oxide nanomaterials with the National Physical Laboratory (NPL) for use in sensor systems. A final area of interest is the development of chalcogenide materials for applications such as optical amplifiers and lasers through to medical devices and memory. This research area is attracting leading researchers in academia and industry due to the significant potential of these materials to revolutionise current optoelectronic technology.

    Experimental techniques I utilise in my research include steady-state (UV-Vis-NIR, FTIR, Raman, PL, PLE, EL) and ultrafast (pump-probe and transient) spectroscopy and laser modification of materials and waveguide device fabrication. I also use SEM, AFM, TEM, UPS, XPS, electrochemistry (CV)  and high magnetic field (> 7 T) measurments in collaboration with others.

    Email: r.j.curry@surrey.ac.uk
    Phone: 2713


    Advanced Hybrid Organic-Inorganic Photovoltaic Architectures

    Supervisor:  Dr Richard Curry
    Co-Supervisors:   Prof. S. Ravi P. Silva

    Type of project: Experiment

    Major Aims
    This research project will focus on advancing the state of the art in hybrid organic-inorganic photovoltaics (HOPVs). Through the use of interfacial modification within HOPVs and smart materials combinations devices with improved efficiency will be developed. Key aims are to increase light harvesting and charge extraction simultaneously using nanostructured materials fabricated using low-cost facile methods.

    Techniques Used
    The project will utilise the significant infrastructure available within the ATI. Nanomaterials growth, patterning and device fabrication will be carried out using the facilities within the cleanroom and related laboratories. Optical and electronic characterisation will be undertaken using a solar simulator and related equipment. Detail optical studies on nanostructures will also be undertaken using laser-based spectroscopy.


    Development and Application New Quantum Dot Materials

    Supervisor:  Dr Richard Curry
    Co-Supervisors:   Professor Jeremy Allam

    Type of project: Experiment

    Major Aims
    A series of novel and previously unstudied quantum dot systems have been developed by collaborators at King's College London. This project will aim to characterise these materials for their optoelectronic properties with the aim of guiding future synthesis and applying the materials future optoelectronic devices. In particular doping of the quantum dot will be studied as a means of selectively controling properties suitable for use in lasing devices.



    Techniques Used
    This project will mainly rely of optical laser-based characterisation of the materials along with some electrical studies at a later stage.

    Collaborations
    King's College London

    Online Reference
    http://www.ee.surrey.ac.uk/LAE/


    Novel Host Materials for Optoelectronic Applications

    Supervisor:  Dr Richard Curry

    Type of project: Experiment

    Major Aims
    The development of efficient emitters for optoelectronic applications has been the focus of much research. However, to allow the continued development of display, lighting and laser technologies for optical communications and processing new materials must be discovered that satisfy ever more demanding requirements. This project will study a number of semiconducting chalcogenide material systems with the aim of developing a multifunctional host medium into which emitters can be doped. The development of such a host system may enable electrical excitation of the emitters, novel waveguiding and photonic bandgap devices, and widely tuneable low-cost high-efficiency light sources to be realised.

    Techniques Used
    The project will use material deposition and modification routes including sputtering and ion-implantation. Standard (absorption, photoluminescence, excitation, lifetime etc) spectroscopy techniques will be used to characterise the materials. Any semiconducting properties (charge mobility etc) will be measured using standard electrical methods. Materials found to be suitable for further study will be formed into a variety of structures including optical waveguides.

    Collaborations
    University of Southampton
    University of Cambridge

    Prof John M Shannon

    Professorial Research Fellow

    Short biography:

    John M Shannon was awarded a D.Sc (doctor of Science) from Brunel University London in 1982.From 1985 to 1994 he was head of Display and Large Area Electronics Groups at Philips Research Laboratories Redhill before sharing his time with the University of Surrey where he is a Professorial Research Fellow within the School of Electronics and Physical Sciences. Professor Shannon has numerous papers and patents in the field of semiconductor devices and was elected Fellow of the Royal Academy of Engineering London in 2001.

    Research Interests:

    Physics and Engineering of Semiconductor Devices. Recently has concentrated on devices in highly disordered semiconductors for large area electronics.

    The source-gated transistor was discovered at Surrey in 2001. For more information please visit http://sgt.hostzi.com/.

    Email: j.shannon@surrey.ac.uk
    Phone: 9310


    High Speed Electronics

    Supervisor:  Prof John M Shannon
    Co-Supervisors:   Prof. S. Ravi P. Silva

    Type of project: Experiment

    Major Aims
    1. Carbon nanotube-composite displays: We are expanding upon our recent success in using carbon nanotube-polymer composites in field emission displays. By dissolving carbon nanotubes in polystyrene and then producing polymer composite cathodes we are able to control the electron field emission characteristics so that we can develop a possible candidate for the next generation of flat panel displays.

    2. Carbon nanotube-composite sensors: Using the results from our study of carbon nanotube-polymer composites we believe that there are novel ways to produce stress sensors by monitoring field emission currents. The exponential increase in field emission current will be exploited to produce high resolution devices that will need to be packaged into device structures using the MEMS fabrication facility at the ATI.

    Techniques Used
    Electrical charcterisation, electron field emission, carbon nanotube technology

    Collaborations
    High speed electronics: We have recently patented a high speed amorphous silicon transistor based on silicide and amorphous silicon technology. This project will look at ways to significantly improve these new electronic devices. Parts of this project also involve Philips' Research Laboratories, Redhill.

    Online Reference
    http://www.ee.surrey.ac.uk/LAE/

    Dr Maxim Shkunov

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Lecturer in Nano Electronics

    Short biography:

    Maxim Shkunov studied physics and applied mathematics at Moscow Institute of Physics and Technology and received his PhD in condensed matter physics from the University of Utah, USA, where he conducted research in ultrafast spectroscopy and laser action in conjugated polymers and photonic crystals. His current research interests focus on organic semiconductors, self-assembly, nanowire electronics and stimulated emission in polymer films. He has over 15 years of experience in the field and worked at Russian Academy of Sciences (Moscow), Cavendish Laboratory (U. Cambridge), and Merck Chemicals (UK).  Maxim (co)-authored more than 80 publications, including articles in peer reviewed journals and patents. He is now a Lecturer in Nanoelectronics at the Advanced Technology Institute. He teaches MSc-level Molecular Electronics and Level 2 Electronic and Photonic Devices and leads PhD and MSc research projects.

    Email: m.shkunov@surrey.ac.uk
    Phone: 6082


    Functionalised metal-oxide nanowires

    Supervisor:  Dr Maxim Shkunov

    Type of project: Experiment

    Major Aims
    Dramatically improve performance of semiconducting nanowire based devices (photovoltaics, sensors, transistors, batteries) via systematic surface functionalisation using self-assembled organic monolayers.

    The Student Will Require
    - have good background in either of the disciplines: electronic engineering, physical chemistry, materials, physics
    - have good hands-on and analytical skills
    - demonstrated excellent aptitude for research

    Project Description
    Nanowires are extremely attractive candidates for nanoelectronic devices. Yet, surfaces of theses nano-rods often suffer from oxide non-regularities and ambient contamination resulting in poor device performance. In this project metal oxide nanowires such as ZnO that are free from native-oxide problems will be functionalised with organic molecules. This organic “passivation” is expected to dramatically improve device performance by removing surface states, passivating from the ambient and changing energetics of semiconductor interfaces. Within the project nanowires will be synthesised, functionalised, thoroughly characterised and then implemented into functional devices to perform electrical measurements.

    Further Reading
    Issue of Materials Today: Nanowires and Nanotubes, Electronics and Photonics in one dimension, October 2006, Volume 9, Number 10


    Nanostructured organic-inorganic supercapacitors

    Supervisor:  Dr Maxim Shkunov

    Type of project: Experiment

    Major Aims
    To investigate novel organic-inorganic nanostructures based on conjugated polymers, carbon nanoparticles and semiconducting nanomaterials for high energy density storage supercapacitors.

    Techniques Used
    - Nanostructured conducting/semiconducting films fabrication and measurements
    - Nano characterisation using AFM, SEM, TEM
    - Ink-jet printing and spray-coating
    - Self-assembly and templating
    - Modelling of electronic properties

    The Student Will Require
    - have a good background in one of the following: electronic engineering, physics, materials, physical chemistry;
    - possess strong practical and analytical skills;
    - have an excellent aptitude for research

    Project Description

    Fig. 1 Example of nanostructured ‘template’ of a synthetic opal crystal surface that can be coated with conducting polymer/nanoparticle composites. (spheres diameter is < 200nm)
    Increasing energy demands for portable electronics and electric vehicles as well as the necessity for an efficient energy storage for intermittent renewable resources (wind and solar) require devices that can be charged very quickly, deliver high power density and sustain thousands of charge-discharge cycles.
    Conventional lithium-ion batteries have high specific energy density, but suffer from short life-time and limited power density that they can deliver.
    Supercapacitors offer a breakthrough in energy storage area due to very high power capabilities and much longer lifetimes than batteries.
    At the heart of every supercapacitor is a nanostructured electrode-electrolyte interface that determines energy storage capacity of the device.
    In this project we will aim to develop supercapacitors with nano-scale electrode materials, based on very high surface area composites of nanotubes/nanowires and conjugated polymers. Surface ‘templating’ (as in Fig. 1) can be used to create micro-porous films with optimised surface area to increase electrode-electrolyte integrations.
    We will also look at possibilities of creating printable, flexible, and transparent electrode supercapacitors using ink-jet printing and spray-coating techniques.

    Further Reading
    X.Zhao et al, Nanoscale, 2011, 3, 839-855


    Organic-inorganic p-n junctions and energy harvesting

    Supervisor:  Dr Maxim Shkunov

    Type of project: Experiment

    Major Aims
    Explore organic-inorganic nanostructures based on conjugated polymers and nanowires for energy harvesting applications including photovoltaics

    Techniques Used
    - Nanostructured conducting/semiconducting films fabrication and measurements
    - Nano characterisation using AFM, SEM, TEM
    - Nanowire deposition and alignment
    - Self-assembly and templating
    - Organic semiconductor ink-jet printing
    - Modelling of electronic properties

    The Student Will Require
    The applicant will need to:
    - have a good background in one of the following: electronic engineering, physics, materials, physical chemistry;
    - possess strong practical and analytical skills;
    - have an excellent aptitude for research.

    Project Description
    Powering miniature autonomous sensors and on-chip radios is one of the biggest challenges in making portable devices that can gather local information and transmit it to a remote reader. Small-size solar panels offer an elegant solution to this problem.
    In this project we will aim to develop organic-inorganic photovoltaic devices based on ‘planar’ oriented nanowire arrays, serving as one side of ‘p-n’ junction and a layer of conjugated polymer printed on top to be the second part of the junction. This approach will enable flexible miniature solar cells that can be integrated into plastic self-powering sensors and smart electronic tags.

    Further Reading
    References:
    -Materials Today: Nanowires and Nanotubes, Electronics and Photonics in one dimension, October 2006, V 9, Number 10.
    -IEEE Spectrum, April 2011, p16


    Towards rollable displays: printed electronics

    Supervisor:  Dr Maxim Shkunov

    Type of project: Experiment

    Major Aims
    To develop high performance printed electronic devices on plastic foils for rollable displays. Explore charge transport and injection at dielectric/semiconductor and metal/semiconductor interfaces.
    Exploit ink-jet printing capabilities do deposit functional nanomaterials.
    Study evolution of devices properties when semiconducting component size is shrunk from tens of micron to sub-micron range. Investigate environmental stability of the devices and develop understanding of degradation mechanisms.

    Techniques Used
    Solution based deposition of semiconducting layers
    Ink-jet printing
    Characterisation techniques AFM, SEM
    Self-assembled monolayer deposition; Nano-imprint
    Field-effect transistor fabrication and characterisation of flexible foils

    The Student Will Require
    - to be open towards multidisciplinary research
    - have good hands-on skills
    - have good background in either of the disciplines: electronic engineering, physics, materials, physical chemistry

    Project Description

    Fig. 1 Photograph of an array of transistors and capacitors on plastic substrate
    Novel printable semiconductors, based on nanomaterials and conjugated molecules, are now demonstrating high charge carrier mobility exceeding that of amorphous silicon. This dramatic progress is opening up possibilities for flexible displays such as pocket-size maps and even rollable TVs. The challenge remains to develop high performing field-effect transistors on plastic substrates to switch pixels in these displays (Fig. 1).
    Current aim is to use “wet” assembly of the semiconducting component and also device electrodes using solvent-based deposition processes including dip-coating, spin-coating, screen-printing or ink-jet printing.
    In this project we will be using a range of semiconductor materials such as organic molecules, inorganic nanowires and carbon nanotubes, all suitable for deposition of plastic substrates. Both charge transport and injection from a range of electrodes will be optimised to achieve high switching speeds. Minimising transistor channel length will help to increase the refresh rates and also improve viewing characteristics of flexible displays.

    Further Reading
    Nanowires and Nanotubes:
    Issue of Materials Today: Nanowires and Nanotubes, Electronics and Photonics in one dimension, October 2006, Volume 9, Number 10

    Organic semiconductors:
    G. Malliaras, R. Friend, An Organic Electronics Primer, Physics Today, May 2005, pp53-58


    Transparent Nanowire Electronics

    Supervisor:  Dr Maxim Shkunov

    Type of project: Experiment

    Major Aims
    To investigate novel semiconducting nanowire nanomaterials as active layers for transparent flexible electronic components and to explore electronic properties of field-effect transistors on plastic foils based on these nanowires.

    Techniques Used
    Field-effect transistor fabrication and electrical characterisation
    Deposition of nanomaterials thin films
    Alignment of nanowires
    Nano characterisation using AFM, SEM
    Metal electrode photolithography


    The Student Will Require
    - have good background in either of the disciplines: electronic engineering, physics, materials, physical chemistry
    - have good hands-on and analytical skills
    - demonstrated excellent aptitude for research

    Project Description
    Nanotechnology has been promising breakthroughs both in the science area and also in everyday life for a number of years. Yet, we notice only limited number of products that resulted from this work. We are all familiar with sun-block creams based on oxide nanoparticles and perhaps carbon fibres in portable laptops lids. In computer chips most of electronic “building blocks” are also in nanometre-scale.
    Indeed, there is a huge scope for nanoscience to enter our lives. One of the areas is flexible electronics such as proposed roll-up television screens and pull-out portable interactive web-displays. To enable such flexible displays the switching of the pixels will need to be performed by “deformable” transistors. Due to these ‘bending’ requirements traditional “rigid” single crystal silicon technology does not work, and novel semiconductor approaches are urgently required. Moreover, transparency of the display is another very attractive feature that is often required in applications like windshield/cockpit windows and head-on display.
    The goal of this work is to bring nanomaterials into real world via flexible electronics route. This can be achieved by using solution processable inorganic semiconducting nanowires formulated into functional ‘inks’. These inks could be then deposited by simple solution-coating methods onto variety of substrates, including plastics to produce transparent semiconducting layers for electronic devices. Due to small aspect ratio these nanowires are fully compatible with ‘bending’ requirement.
    For full flexibility the device structures are completed by depositing printable electrodes and plastic dielectric layers.

    Further Reading
    Issue of Materials Today: Nanowires and Nanotubes, Electronics and Photonics in one dimension, October 2006, Volume 9, Number 10

    Prof. S. Ravi P. Silva

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Professor of Solid State ElectronicsDirector of ATIHead of Nano-Electronics Centre

    Short biography:

    Ravi Silva is the Director of the Advanced Technology Institute (ATI) and heads the Nano-Electronics Centre (NEC), which is an interdisciplinary research activity. The NEC has over 50 research staff. He joined Surrey in 1995. Ravi's secondary education was in Sri Lanka, after which he joined the Eng. Dept. at Cambridge Univ. for his undergraduate and postgraduate work.

    His research has resulted in over 330 presentations at international conferences, and over 320 journal papers.

    In 2002 he was awarded the Charles Vernon Boys Medal by the Inst. of Physics, and in 2003 he was awarded the IEE Achievement Award by the Inst. of Elec. Engineers.

    In 2003 he was also awarded the Albert Einstein Silver Medal and Javed Husain Prize by UNESCO for contributions to electronic devices.

    In 2003 the largest EPSRC Portfolio award for £6.68M was made to Prof. Silva and his team on Integrated Electronics, which was followed in 2004 by a SRIF award for £4M to set up a Nano-Electronics Centre for multidisciplinary research.

    In 2005, the Nano-Electronics Centre was a finalist in the Emerging Technologies category of the IEE 2005 Awards for Innovation in Engineering.

    In 2007, Prof. Silva was the runner-up of the "Times Higher Education Young Scientist of the Year", and "Most Entrepreneurial Scientist 2007, United Kingdom", by UKSEC and Science Alliance of the Netherlands.  He was elected a Fellow of the Royal Society of Arts in 2007.

    In 2008 he was elected a Fellow of the Royal Academy of Engineering, UK.

    Prof. Silva was on the advisory board of Imprimatur Ltd and the National Nanotechnology Initiative (NNI) of Sri Lanka.  He spent the year 2008 acting as an Advisor to the Honourable Minister of Science and Technology in Sri Lanka Institute of NanoTechnology (SLINTec) and the Nano-Science Park and Centre, NANCO (private) Ltd.  He acts as an advisor to both these activities and is on the director's board.

    Prof. Silva was also a member of the Electrical and Electronic Panel (UoA24) for the recently concluded Research Assessment Exercise 2008 (RAE2008), EPSRC Nanotechnology Task Force and currently sits on the Engineering and Physical Sciences Research Council's (EPSRC) Technology Opportunities Panel (TOP).

    Research Interests:

    His research interest encompass a wide range of activities. Nano-Electronics and renewables being two themes that are very important to the whole effort.
    In addition to Nano-Electronics, the characterisation, growth and processing of novel semiconductor materials for large area electronic applications is central to the group activity. Novel device structures & physic of carbon nanotubes and photovoltaics based on polymer/nanotube composites, electron field emission from amorphous materials and modelling of the emission, photovoltaics, electroluminescent cells, electronic doping of amorphous carbon, Excimer laser annealing and ablation, disordered (amorphous and n-C) GaN for optoelectronic applications, band gap modulated superlattice structures, diamond and SiC thin film deposition, the use of ion implantation for electronic doping and synthesis of novel materials are some of his other interests.
    Research is progressing rapidly on growth kinetics of low temperature carbon nanotubes.

    Email: s.silva@surrey.ac.uk
    Phone: 9825


    Carbon Based Electronics

    Supervisor:  Prof. S. Ravi P. Silva
    Co-Supervisors:   Dr David Carey

    Type of project: Experiment

    Major Aims
    Three PhD projects in

    1. Carbon Superlattice Devices: The LAE&N group are part of a UK wide consortium of leading research groups in the UK examining the use of carbon based materials for electronics. One project involves the growth and characterisation of novel superlattice structures based on different type of amorphous carbon from diamond-like carbon to polymer like carbon. Our deposition systems are capable are producing a wide variety of material and this project will look at the optical as well as the electrical properties.

    2. Laser ablation and pulsed laser deposition of carbon nanostructure: Using our excimer laser and associated deposition system we aim to grow and characterise nanotubes, nanoparticles, diamond based materials etc with a view to incorporating them in devices such as field emission displays and smart dust applications.

    3. Large Area devices based on amorphous carbon alloys: It is possible by clever changes in deposition conditions to be able to produce a wide range of amorphous carbon related alloys including a-SiC, and a-CN. The aims of this project are to grow and characterise the electrical and optical properties of the materials for both passive and active electronics

    Techniques Used
    Deposition, optical and electrical charcterisation of different types of carbon and diamond-like carbon materials.

    Online Reference
    http://www.ee.surrey.ac.uk/LAE/


    Large Area Electronics

    Supervisor:  Prof. S. Ravi P. Silva
    Co-Supervisors:   Dr David Carey

    Type of project: Experiment

    Major Aims
    1.Transparent electronics: Using plastic or glass or paper for electronics!!! It sounds weird but it is possible to use transparent materials for advanced electronics applications (not that paper is transparent!). In this project we will examine the electronic properties of a host of materials with a view to optimise their properties for practical large area electronic applications. Parts of this project involve Philips' Research Laboratories, Redhill.

    2. Solar cells and photovoltaics: Using a range of polymer and other materials we aim to improve on the photo-efficiency of large area solar cell materials. Amorphous carbon, polymer/nanotube composites and amorphous silicon/crystallised will be employed.

    Techniques Used
    Electrical charcterisation of devices

    Online Reference
    http://www.ee.surrey.ac.uk/LAE/


    Nanotechnology: Applications of Carbon Nanotube-Composites

    Supervisor:  Prof. S. Ravi P. Silva
    Co-Supervisors:   Dr David Carey

    Type of project: Experiment

    Major Aims
    Three PhD projects in

    1. Carbon nanotube-composite displays: We are expanding upon our recent success in using carbon nanotube-polymer composites in field emission displays. By dissolving carbon nanotubes in polystyrene and then producing polymer composite cathodes we are able to control the electron field emission characteristics so that we can develop a possible candidate for the next generation of flat panel displays.

    2. Carbon nanotube-composite sensors: Using the results from our study of carbon nanotube-polymer composites we believe that there are novel ways to produce stress sensors by monitoring field emission currents. The exponential increase in field emission current will be exploited to produce high resolution devices that will need to be packaged into device structures using the MEMS fabrication facility at the ATI.

    3. 3D manipulation of carbon nanotubes: We have developed techniques to manipulate nanostructures to bespoke device configurations, opening the door for the fabrication of prototype electronic devices. This research is currently under patent.



    Techniques Used
    Mnaipulation, structure of carbon nanotubes, electron field emission

    Online Reference
    http://www.ee.surrey.ac.uk/LAE/

    Professor Bernard L Weiss

    Professor of Microelectronics and Pro-Vice-Chancellor

    Short biography: Bernard graduated from the University of Newcastle-upon-Tyne with a BSc(Hons) in Electrical Engineering in 1971 and a PhD in microwave semiconductor devices in 1975. Following a personal SRC Postdoctoral Research Fellowship in microwave semiconducor devices and a Wolfson Foundation Research Fellowship, he moved to University College London in 1977 to study ZnO acoustic transducers and NDT. In 1979 he joined Surrey University as a Lecturer establishing research in optoelectronic devices and technology in LiNbO3, Si and III-V semiconductors. He became Professor of Microelectronics in 1996, Head of the School of Electronics and Physical Sciences in 2001 and Pro-Vice-Chancellor in 2005.

    He was an Honorary Professor at the University of Hong Kong (1996-2000) and has held visiting appointments at the University of Berkeley, California (1981), University of Cincinnati, Ohio (1991), Technische Hochschule Darmstadt, (1994) and the University of Michigan at Ann Arbor (2000).

    Research Interests: His current research is concerned with optoelectronic and microwave devices, integrated antennas and nanotechnology and nanoelectronics and their application to medicine and biology.

    Email: b.weiss@surrey.ac.uk
    Phone: 9128


    MEMS and diamond

    Supervisor:  Professor Bernard L Weiss
    Co-Supervisors:   Prof. S. Ravi P. Silva

    Type of project: Experiment

    Major Aims
    Micomachining/MEMS: We have processes that allow us to produce deep trench structures for use in microwave applications by a state of the art reactive ion etching system. Samples are grown/etched and characterised in the ATI using a wide range of electrical techniques.

    Techniques Used
    Deposition, optical and electrical charcterisation of different types of carbon and diamond-like carbon materials. Growths of microelectromechanical systems

    Online Reference
    http://www.ee.surrey.ac.uk/LAE/

    Theory and Advanced Computation

    http://www.ati.surrey.ac.uk/tac

    Dr David Faux

    Senior Lecturer

    Short biography:

    David obtained a First Class Honours degree in Physics  from Nottingham University, UK (awarded 2 academic prizes), a MSc in Physics and Technology of Nuclear Reactors from Birmingham University, UK and a PhD from Birmingham University, UK, in 1986.  He then spent 2 years at North Carolina State University, Raleigh, NC, USA supported by a NATO Fellowship.  He was apponted as a Lecturer at the University of Surrey in 1988 and promoted to Senior Lecturer in 1985.  David was appointed Deputy Dean of Students in 2005 on a 50% basis and is located in the Advanced Technology Institute.

    Research Interests:

    David's is a theoretical/computational condensed matter physicist with current research interests focusing on molecular dynamics simulations of carbon nanotubes in fluids.  One area of activity examines the behaviour of water in and around nanotubes with desalination and energy generation being possible applications of carbon nanotube technology. 

    David is an expert in molecular dynamics and Monte Carlo simulation methods. We are currently using molecular dynamics to explore the behaviour of liquid mixtures under pressure in an attempt to understand the "solvation pressure" effect and to tie up with Raman experimental data. This is important for the study of protein folding.

    David's previous research interests focussed chiefly on the modelling of stress/strain and piezoelectric fields in semiconductor quantum wires and dots. Numerical procedures, Green's functions, fourier methods and atomistic simulations were used to determine the stress/strain fields which are of paramount importance in the determination of novel semiconductor device properties.

    Email: d.faux@surrey.ac.uk
    Phone: 6792


    Dynamics of water in confined nano-spaces

    Supervisor:  Dr David Faux
    Co-Supervisors:   Professor Peter McDonald

    Type of project: Experiment and Theory

    Major Aims
    1) To undertake equilibrium molecular dynamics simulations to develop an improved understanding of the dynamics of water in and around carbon nanotubes;

    2) To calculate functions used in experimental work to elucidate the dynamic properties of water (neutron scattering functions, NMR relaxation rates)

    3) To undertake NMR relaxations measurements, including novel relaxation exchange and correlation measurements, of water/CNT systems;

    4) To interpret the NMR experimental results in terms of the simulation;

    Techniques Used
    The atomistic simulations will be performed using DLPOLY, a software package created at Daresbury Laboratory. We have about 15 years experience using DLPOLY. The code can be run on the local super-computer. Local expertise exists through a PDRA and PGR students.

    NMR measurements may be undertaken using facilities housed in the Physics Department. Professor Peter McDonald is an expert in this area.



    Source of Expertise
    Dr David Faux is an expert on molecular dynamics (MD) and on the use of the DLPOLY software package with 15 years experience exploring hydrated systems (water/zeolites & water/ethanol) and carbon nanotubes. David is an expert on the interpretation of simulation data in terms of neutron scattering functions and NMR relaxation rates and Peter McDonald is an expert on the behaviour of fluids in confined spaces (in a wide variety of systems) and its characterisation using a range of NMR techniques and instruments, some developed in-house.

    The Student Will Require
    This is a joint computational/experimental project. The student should be keen to develop their computational and modelling skills and be prepared to develop their own code in FORTRAN or C++. The experimentation will be performed using Physics Department facilities.

    Project Description
    There is significant interest at the fundamental level in the behaviour of water in confined spaces. Systems of interest include cements, zeolites and plastics. Recently, this interest has extended to carbon nanotubes. In cements, for instance, the combination of MD simulation and NMR measurement at international level has underpinned significant advances: see J.-P. Korb, P.J. McDonald, L. Monteilhet, A.G. Kalinichev and R.J. Kirkpatrick, “Comparison of proton field-cycling relaxometry and molecular dynamics simulations for proton–water surface dynamics in cement-based materials ” Cement and Concrete Research. 37, 348-350, (2007)

    Carbon nanotubes (CNTs) are essentially graphene (a single layer of graphite with a hexagonal sp2 hybridised structure) rolled into a tube. Water/nanotube systems have attracted much research interest due to potential applications in desalination, energy-generating membranes, fuel cells and drug delivery. Moreover, the water/CNT system acts as an excellent, reasonably-well-characterised model system for fluids in confined spaces and water may enter the tube in addition to surrounding it. Thus, some water is mobile, as in its bulk, and a portion has restricted motion due to confinement within the tube.

    This project involves developing a fundamental understanding of the properties of water/CNT systems jointly with professor Peter McDonald. The computational component involves molecular dynamics simulation using DLPOLY software on the local supercomputing cluster. The interpretation of data in terms of neutron scattering functions has been trialled during the past year and is promising. It should be possible, also, to use the simulated dynamical data to simulate the output of NMR experimentation depending on the feasibility of the modelling timescales.

    The experimental work would be undertaken using existing NMR facilities within the Physics Department. Some preliminary experiments have already, with curious results, been performed on the CNT/water system and the student would build on this work.



    Hydrated Carbon Nanotubes

    Supervisor:  Dr David Faux
    Co-Supervisors:   Professor Ortwin Hess

    Type of project: Theory

    Major Aims
    1) To undertake equilibrium atomistic simulations of hydrated carbon nanotubes

    2) To understand the behaviour of water in and around carbon nanotubes, especially its dynamical properties and the effect of solvation pressure on bond lengths,

    3) To simulate the Raman spectra of solvated carbon nanotubes.

    Techniques Used
    The atomistic simulations will be performed using DLPOLY, a software package created at Daresbury Laboratory. We have about 15 years experience using DLPOLY.

    Source of Expertise
    Dr David Faux is an expert on molecular dynamics (MD) and on the use of the DLPOLY software package with 15 years experience exploring hydrated systems (water/zeolites & water/ethanol). A final year PhD student (supervised by Professor Hess) is undertaking some non-equilibrium MD on hydrated nanotubes and a second year PhD student (supervised by Dr David Faux)is working in a related area.

    The Student Will Require
    This is a computational project. The student should be keen to develop their computational and modelling skills and be prepared to develop their own code in FORTRAN or C++.

    Project Description

    Hydrated nanotube
    There has been considerable interest in the general field of water in confined spaces - for example, water in to pores & cages of zeolite crystals (washing powder technology), water on cement surfaces (construction), water in rocks (oil extraction). Recently, there has been significant interest at the fundamental level in the behaviour of water in carbon nanotubes with some properties (for example, the diffusion rate of the water) being poorly understood.

    The student would undertake equilibrium molecular dynamics simulations of water (using atom-specific potentials) and carbon nanotubes to attempt an understanding both of the structural and diffusional behaviour of the water and also to determine the effect of the solvation pressure that the water is predicted to exert on
    the nanotubes. This work complements some existing research by Ortwin Hess/James Cannon currently underway.

    This is an opportunity for a student to make a significant impact in an exciting area of current research.

    Further Reading
    Liu YC, Wang Q
    Transport behavior of water confined in carbon nanotubes
    PHYSICAL REVIEW B 72 (8): Art. No. 085420 AUG 2005

    Hummer G, Rasaiah JC, Noworyta JP
    Water conduction through the hydrophobic channel of a carbon nanotube
    NATURE 414 (6860): 188-190 NOV 8 2001


    Nanomechanics of Graphene

    Supervisor:  Dr David Faux
    Co-Supervisors:   Dr. Alan Dalton

    Type of project: Experiment and Theory

    Major Aims
    1) To undertake equilibrium atomistic simulations of graphene sheets using molecular dynamics to develop an improved understanding of its properties;

    2) To investigate the mechanical properties of graphene, particularly its Raman spectra (determined from its vibrational properties);

    3) To undertake some Raman spectroscopy experiments on graphene sheets;

    4) Undertake simulations of graphene in different environments (stressed, aqueous)

    Techniques Used
    The atomistic simulations will be performed using DLPOLY, a software package created at Daresbury Laboratory. We have about 15 years experience using DLPOLY. The code can be run on the local super-computer. Local expertise exists through a PDRA and PGR students.

    Raman measurements will be performed using to local Raman facility housed in the Physics Department. Dr Alan Dalton is an expert in this area.



    Source of Expertise
    Dr David Faux is an expert on molecular dynamics (MD) and on the use of the DLPOLY software package with 15 years experience exploring hydrated systems (water/zeolites & water/ethanol) and carbon nanotubes. MD has been used successfully to determine Raman spectra in ethanol and water/ethanol systems.

    The Student Will Require
    This is a computational project with the opportunity for experimentation. The student should be keen to develop their computational and modelling skills and be prepared to develop their own code in FORTRAN or C++. The experimentation will be performed using Physics Department facilities.

    Project Description
    Recently, there has been significant interest at the fundamental level in the behaviour of carbon nanoparticles (such as carbon nanotubes and graphene). Graphene (a single layer of graphite with a hexagonal sp2 hybridised structure)is the strongest material known to man (and currently the most expensive!). The mechanical properties of graphene is not well established and its Raman characteristics, for example, have only recently been established experimentally. This is therefore an opportunity to make an impact in a young field.

    This project involves developing a fundamental understanding of the mechanical properties of graphene jointly with Dr Alan Dalton. The computational component involves molecular dynamics simulation using DLPOLY software on the local supercomputing cluster. The identification of appropriate interatomic potentials will be key. The interpretation of data and production of simulated Raman spectra has not been attempted before for graphene but the technique has been implemented successfully in other systems and, provisionally, for carbon nanotubes. The results will have implications for the interpretation of spectra from carbon nanotubes too.

    Professor Ortwin Hess

    " style="float:right; margin: 0 20px 0 20px; width:200px;" />Leverhulme Chair in Metamaterials at Imperial College London

    Short biography:

    Professor Ortwin Hess is Visiting Professor in the Department of Physics and Advanced Technology Institute. He holds the Leverhulme Chair in Metamaterials in the Department of Physics at Imperial College London. Ortwin studied physics at the University of Erlangen and the Technical University of Berlin. Following post-doctoral times in Edinburgh and at the University of Marburg Ortwin has been (from 1995 to 2003) Head of the Theoretical Quantum Electronics Group at the Institute of Technical Physics in Stuttgart, Germany. He has a Habilitation in Theoretical Physics at the University of Stuttgart (1997) and became Adjunct Professor in 1998. Since 2001 he is Docent of Photonics at Tampere University of Technology in Finland. Ortwin has been Visiting Professor at Stanford University (1997 - 1998) and the University of Munich (2000 - 2001). From 2003-2010 he held the Chair of Theoretical Condensed Matter and Optical Physics in the Department of Physics and the Advanced Technology Institute.

    Research Interests:

    Ortwin’s interests are focused on metamaterials, nano-plasmonics and photonics (slow light, laser dynamics and bio-photonics). Together with his group Ortwin has made pioneering contributions to the theory of slow light in metamaterials (the ‘Trapped Rainbow’, Nature, 15 Nov 2007 and several subsequent publications in Nature), to (ultrafast) spatio-temporal dynamics and quantum fluctuations of semiconductor, quantum dot and fibre lasers as well as to the quantum theory of temperature on the nano-scale. Ortwin’s research interests and objectives bring together a broad range of theoretical techniques. In his group, a large variety of advanced computational methods and simulation tools are developed and used on high-performance computing platforms to explore the nano-space and ultrafast (quantum) dynamics of metamaterials, complex nano- and bio-photonic systems and novel lasers to harness the quantum nature of electrons and photons on the nano-scale and ultrafast timescales.

    Email: o.hess@surrey.ac.uk
    Phone: 2745


    'Trapped Rainbow' Storage of Single Photons in Metamaterials

    Supervisor:  Professor Ortwin Hess
    Co-Supervisors:   Dr Aleksey D Andreev

    Type of project: Theory

    Major Aims
    To develop a quantum-theoretical approach to slow light and light storage in metamaterials and explore the potential to store non-classical light fields such as single photons based on the 'trapped-rainbow' principle.

    Techniques Used
    analytic theory
    finite-difference time-domain simulation

    Project Description
    Recently we have proposed the 'Trapped Rainbow' scheme for slowing down and eventually trapping light, having demonstrated that an axially varying heterostructure with a core of negative refractive index metamaterial can be used to efficiently and coherently bring light to a complete standstill. In stark contrast to previously proposed schemes for decelerating and storing light, the present one simultaneously allows for high in-coupling efficiencies and broadband, room-temperature, operation.

    Analytic theoretical analysis reveals that at a critical point the effective thickness of the waveguide reduces to zero, preventing the lightwave to propagate further. At this point, a light ray is found to be permanently trapped, its trajectory forming a double light-cone that we call an ‘optical clepsydra’. Each frequency component of a wave packet is stopped at a different guide thickness, leading to the spatial separation of the packet’s spectrum and the formation of a ‘trapped rainbow’.

    Since the 'Trapped Rainbow' scheme relies on a linear effect it offers the potential of storing single photons are required in quantum optical memories.


    Attosecond Nanophotonics

    Supervisor:  Professor Ortwin Hess

    Type of project: Theory

    Major Aims
    To explore the attosecond dynamics of light and matter on the nanoscale and study extreme nonlinearities and the spatio-temporal dynamics of electrons in strong laser fields.

    Techniques Used
    Finite-difference Time-Domain simulations coupled with the Schroedinger Equation

    Project Description
    The recent development of new XUV and soft X-ray lasers has opened up completely new opportunities for the physics on sub-femtosecond time scales. The project would involve the development of a theory for the spatio-temporal dynamics of photonic nanomaterials on attosecond time-scales. Thereby a multitude of intriguing effects need to be taken on board that allow a strong drive towards visualising the internal dynamics of nanomaterials.


    Complex Nanomaterials for Quantum Memories

    Supervisor:  Professor Ortwin Hess
    Co-Supervisors:   Dr Edeltraud Gehrig, Dr David Faux

    Type of project: Theory

    Major Aims
    The project aims to model quantum nanomaterials on the basis of self-organized semiconductor
    quantum dots and study the interaction of these with ultrashort light pulses. The fidelity as a measure for
    their suitability for quantum memories will be determined.

    The modelling will be performed on the semiclassical as well as the fully quantum levels.

    Techniques Used
    Theory and computational modelling based on mesoscopic models of complex nanomaterials.

    Collaborations
    Dr Dieter Jaksch and Professor Ian Walmsley
    (University of Oxford)

    Project Description
    The ability to deterministically transform quantum states of light to quantum states of matter
    deterministically is both the most fundamental conceivable interaction and vitally important for the
    development of light-based quantum technologies. In particular, it is the basis of a quantum memory,
    without which it will not be possible to build either a long distance quantum communication link or a
    network-model quantum computer. The realization of a quantum memory requires precise knowledge
    of the quantum properties of the material to be utilized. Most current attempts for implementing a
    quantum memory exploit neutral atoms or ions as the storage medium, for which the quantum
    dynamics is well known and relatively easy to describe. For instance, electromagnetically induced
    transparency (EIT) can be used to slow the light down and coherently create an excitation of the
    medium representing the quantum information. The readout is achieved by reversing this unitary
    process. The apparent drawback of using atoms is the large experimental setup which makes it
    impractical for industrial utilization. Therefore, this project seeks ways to replace the storage medium
    with more robust and easy to handle arrays of quantum dots or endohedral fullerenes. These
    nanomaterials, i.e. nanostructured materials with a specifically designed spatial structure have found
    applications in various fields such as quantum dot lasers, semiconductor optical amplifiers, active
    semiconductors with spatially structured waveguiding properties (distributed feedback and distributed
    Bragg reflector lasers) as well as photonic material systems. However, their spatio-temporal coherence
    properties which are of central interest for realizing nanomaterial based quantum memories are very
    little explored: detailed materials modelling will be necessary to understand the (quantum)
    characteristics of light/quantum material interactions and their influence on coherence. In particular,
    precise modelling of an ultrashort single-photon pulse interacting with the nanomaterial will be of
    paramount importance for future applications in quantum information processing.



    Functional Photonic Opals

    Supervisor:  Professor Ortwin Hess
    Co-Supervisors:   Professor Jeremy Allam

    Type of project: Theory

    Major Aims
    Theoretical analysis and computational modelling of functional opal photonic crystals based on the novel
    double-inverse opal structure. Exploration of photonic band-gap switching for control of spontaneous
    emission of quantum dots embedded within the structures.

    Techniques Used
    Finite-Difference Time-Domain (FDTD) simulation tools developed in the TAC group in combination with
    advanced Finite-Element codes provided by collaboration partners.

    Comparision with experimental investigation.

    Project Description
    The concept of producing photonic crystals by modulating the refractive index periodically in all three
    directions has became a major research theme over the last decades. However, the ability to fabricate
    large-scale cost-effective implementations has been impossible. We recently introduced and
    demonstrated a new class of plastic photonic crystals produced through assembly of core-shell
    nanoparticles, which have the inherent possibility for scaling up to industrial scale production for the first
    time. Our work is clearly distinguished from sedimentation and capillary assembly of opal-based
    nanomaterials (which are non-scalable) and offers a new and practical way forward. By doping such
    structures with nanoparticles we have produced a new range of flexible films which possess extremely
    strong structural colour that is widely tuneable.


    Nonlinear Silicon Photonics

    Supervisor:  Professor Ortwin Hess

    Type of project: Theory


    Physics of Photonic Opals for Functional Colour

    Supervisor:  Professor Ortwin Hess

    Type of project: Experiment and Theory

    Major Aims
    To elucidate the physics of polymer-based flexible opal photonic crystals for functional colour. The project will link theoretical analysis with experimental studies and computational modelling to develop models for light diffraction and scattering in polymer opals leading to an understanding of structural colour.

    Techniques Used
    Physics of polymer materials linked on the one hand with Finite-Difference Time-Domain (FDTD) and simulation tools developed in the TAC group in combination with advanced Finite-Element codes developed in collaboration with project partners and on the other hand with optical experiments.

    Collaborations
    Professor Jeremy Baumberg, Cambridge University

    Project Description
    The concept of producing photonic crystals by modulating the refractive index periodically in all three
    directions has became a major research theme over the last decades. However, the ability to fabricate
    large-scale cost-effective implementations has been impossible. We recently introduced and
    demonstrated a new class of plastic photonic crystals produced through assembly of core-shell
    nanoparticles, which have the inherent possibility for scaling up to industrial scale production for the first
    time. Our work is clearly distinguished from sedimentation and capillary assembly of opal-based
    nanomaterials (which are non-scalable) and offers a new and practical way forward. By doping such
    structures with nanoparticles we have produced a new range of flexible films which possess extremely
    strong structural colour that is widely tuneable.

    Further Reading
    http://www3.interscience.wiley.com/cgi-bin/fulltext/112520685/PDFSTART
    http://www.nature.com/nmat/journal/v5/n1/pdf/nmat1562.pdf
    http://www.nature.com/nmat/journal/v5/n3/pdf/nmat1588.pdf


    Quantum Dot Random Lasers

    Supervisor:  Professor Ortwin Hess
    Co-Supervisors:   Dr Aleksey D Andreev

    Type of project: Theory

    Major Aims
    Explore the novel physics of random lasers in ensembles of quantum dots and link the coherence to plasmonic nanomaterials.

    Techniques Used
    Finite-Difference Time-Domain (FDTD) simulation tools developed in the TAC group in combination with advanced Finite-Element codes.

    Collaborations
    Prof Wolfgang Elsaesser, Darmstadt University of Technology, Germany


    Project Description
    Random lasing has recently attracted intense attention:

    (1) Random lasing helps to understand coherent phenomena in disordered media on a fundamental level.

    (2) The principle of random lasing can directly be applied in optoelectronic systems due to easy preparation (i.e. no mirrors required) and due to the small size of typical random lasers down to few microns.

    In random lasers, lasing emerges from special random nano- and micro cavities formed within the active medium.
    Numerical studies on the basis of spatially and temporally resolved simulations allow us to study the performance and properties of such special lasers without the restriction to the expansion in terms of modes of the nano-cavities that is required in analytical approaches. It is easy to understand that since the pioneering work of Letokhov lasing in random media has been in the focus of various investigations.

    In a random laser the lasing process is initiated by disorder-induced scattering. In an active random medium, light is scattered and undergoes a random walk before leaving the device. Generally on can differentiate between two kinds of random lasers:

    (1) lasers with nonresonant (incoherent) feedback and

    (2) lasers with resonant (coherent) feedback.

    In the case of incoherent feedback the scattering of light in the region around the initial light creation process leads to light amplification or, spoken in terms of the photon picture, to the generation of successive photons. The situation is different if light is amplified in resonance. This case occurs if light returns to the scattering centre forming a closed-loop path for light.

    In a spatially extended active nano-medium incoherent scattering is caused by carrier scattering and dipole dephasing whereas coherent contributions arise from either resonant amplification in resonant dots or from the geometrical feedback realized by the boundaries of the cavity.



    Quantum Dot Random Laser

    In the quantum dot random laser, randomness is caused by spatial disorder in quantum dot size and positioning leading to space-dependent charge carrier and inter-level polarization dynamics. The random scattering thus enters the equations through the statistical properties of the decay rates and matrix elements which we assume (but are not limitted to) being Gaussian distributed.

    The light that is locally created by stimulated emission may then travel to surrounding dots where a partially coherent amplification occurs. The coherence properties of the light in the neighboring regions thereby depends on the coherent but spectrally detuned induced emission in the surrounding dots (which may be of different size and exhibit a different transition energy) and on incoherent processes such as carrier and dipole dephasing. The feedback provided by the disorder-induced scattering may thus have a stronger influence on the light field and carrier dynamics than the feedback realized by the laser cavity leading to interesting effects and spatio-spectral emission characteristics.

    Random Lasing in Quantum Dot Semiconductor Optical Amplifiers

    The spatial inhomogeneity in the dot properties of a quantum dot active medium leads to the formation of nano and micro-scaled cavities formed by the partial light scattering in the area surrounding a dot. The gain and loss of the individual nano- and micro cavities thereby is determined by the difference in dot properties.

    In the following we will consider the two limiting cases of high and low disorder. Without loss of generality the percentage of the fluctuations will be set to identical amplitude in all material properties (scattering rates, dipole transitions).


    Quantum Optics of Metamaterials

    Supervisor:  Professor Ortwin Hess
    Co-Supervisors:   Prof Benedict N Murdin

    Type of project: Theory

    Major Aims
    - To develop a quantum-theoretical framework for the optics of negative-index metamaterials: quantum
    transformation-optics.

    - To to apply the theory to metamaterial waveguides and characteristic properties of guided fields such as,
    in particular, the Goos-Haenchen shift.

    - To explore possibilities to generate slow non-classigal light

    - To theoretically and computationally investigate new schemes to control quantum light properties based
    on the 'trapped-rainbow' principle.

    Techniques Used
    analytic theory

    quantum simulation based eg on finite-difference time-domain simulation of the quantized Maxwell's
    equations


    The Student Will Require
    A first class (or equivalent) master degree in physics and a keen interest to explore a new exciting field in
    optics.



    Project Description
    Recently we have proposed the 'Trapped Rainbow' scheme for slowing down and eventually trapping
    light, having demonstrated that an axially varying heterostructure with a core of negative refractive
    index metamaterial can be used to efficiently and coherently bring light to a complete standstill. In
    stark contrast to previously proposed schemes for decelerating and storing light, the trapped rainbow
    simultaneously allows for high in-coupling efficiencies and broadband, room-temperature, operation.

    Classical analytic theoretical analysis reveals that at a critical point the effective thickness of the
    waveguide reduces to zero, preventing the lightwave to propagate further. At this point, a light ray is
    found to be permanently trapped, its trajectory forming a double light-cone that we call an ‘optical
    clepsydra’. Each frequency component of a wave packet is stopped at a different guide thickness,
    leading to the spatial separation of the packet’s spectrum and the formation of a ‘trapped rainbow’.

    Since the 'Trapped Rainbow' scheme relies on a linear effect it offers the potential of storing single
    photons as required in quantum optical memories.

    Initial stages of the project would embrace the aim to develop a suitable quantum theoretical
    foundation for metamaterials with a negative refractive index.

    Professor Michael J Kearney

    Dean of Faculty

    Short biography:

    I was born in Crawley, Sussex, in 1962, but spent much of my childhood in Melbourne, Australia. Returning to England in 1976, I completed my schooling at Lancaster Royal Grammar School before entering St. John's College Oxford in 1982 to study Physics. A PhD in theoretical solid state physics followed at the University of Warwick, whereupon in 1988 I joined the Long Range Research Laboratory at the GEC Hirst Research Centre. After serving a period as Manager of that Laboratory, I left in 1995 to join the Department of Electronic and Electrical Engineering at Loughborough University as Professor of Electronic Device Engineering. Whilst there, I served as Head of Department between 1997 and 2000. I joined Surrey in 2002 as the inaugural Director of the Advanced Technology Institute, and was appointed Head of the School of Electronics and Physical Sciences in January 2005. On August 1st 2007 I became Dean of the newly formed Faculty of Engineering and Physical Sciences.

    Research Interests:

    Many and varied, spanning engineering, physics and mathematics. Examples include (i) electronic and thermoelectric transport in low dimensional disordered materials, (ii) III-V devices for RF and microwave applications (e.g. mixers, detectors, sources), (iii) SiGe heterostructures for FET applications (particularly p-type devices), and (iv) thin-film solar cells (especially amorphous silicon). Recently I have been studying various stochastic processes (both discrete and continuous) which find application to percolation and queueing pehenomena.

    Email: m.j.kearney@surrey.ac.uk
    Phone: 9410


    Modelling mobilities in SiGe FET devices

    Supervisor:  Professor Michael J Kearney

    Type of project: Theory

    Major Aims
    To better understand the mobility of holes in nanoscale SiGe FET devices, where the principal limiting scattering mechanisms are surface roughness, remote impurities and alloy disorder. The precise role of the latter, in particular, is highly controversial, and resolving this issue will play an important part in determining the commercial viability of the technology.

    Techniques Used
    Theoretical modelling (analytical and computer simulation), interpretation and fitting of experimental data (I-V-T).

    Collaborations
    Physics Department, The University of Warwick
    Members of the EPSRC Si Network

    Project Description
    The project involves working closely with experimentalists who are fabricating and measuring state of the art SiGe heterostructure devices. Data provided in terms of I-V-T measurements contains valuable information about the precise scattering rates of holes as they traverse the conduction channel. By constructing models, both analytical and based on computer simulation, one can attempt to determine the precise importance of each scattering mechanism by fitting to the mobility data. In turn, this allows the fundamental limits of the device technology to be estimated, which is important in the context of deciding whether the technology can actualy deliver the anticipated benefits.