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Photonics and Electronics

Photonics and Electronics

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For more , please contact:

Helena Arrand UNIMAT Photonics and Electronics IDTC Research Support and Commercialisation Office University Park Nottingham NG7 2RD

Tel: +44 (0)115 951 5120 Fax: +44 (0)115 951 5616 E-mail: [email protected] www.nottingham.ac.uk/p-e

Contents Introduction

Contents ...... 3 phenomena; modelling of quantum Introduction...... 4 phenomena in electronic and photonic transport; and, nanoscale Biomedical Informatics ...... 5 electronics and optoelectronics. High Power Lasers ...... 6 In EEE, the Applied Optics Group Materials and Device Characterisation ...... 7 (AOG), the George Green Institute for Electromagnetics Research Materials ...... 8 (GGIEMR), and the Photonic and Modelling (1) ...... 9 RF Group (PRFEG) are Modelling (2) ...... 10 active in: ; biomedical imaging; VLSI design; ...... 11 The University of Nottingham has the design and characterisation of an international reputation for Nitride ...... 12 compound devices excellence in its research into and materials; the development of Novel Photonic Glasses ...... 13 areas of photonics and electronics novel modelling techniques to Optical Engineering ...... 14 and has an excellent track record solve complex problems in in working with industry. This ...... 15 photonics and electronics. The brochure gives a taste of some of Power Electronics, and RF Circuits and Systems ...... 16 the exciting and dynamic research Control Group (PEMC) and the Spintronics ...... 17 currently being undertaken. Ultrasonics and Non-destructive VLSI Design...... 18 We have key research groups Evaluation Group (UNDEG), also in based in four Schools: Key Research Groups ...... 19 EEE, have substantial research • and Astronomy activities in power electronics and (Physics) ultrasonics, respectively. • Electrical and Electronic Meanwhile, the Advanced Materials Engineering (EEE) Group (AMG) in M3 has, in recent years, developed a well respected • Mechanical, Materials and activity in Novel Photonic Glasses. Engineering (M3) This group is also home to most of • Chemistry the University’s advanced analysis The research groups have a range and characterisation techniques of interests. In Physics, for and their application to many example, the research activities of materials and devices. the Semiconductor Physics Group Finally, the Materials Chemistry (SPG), the Theoretical Physics expertise in Chemistry is used to Group (TPG) and the Nanoscience understand and develop new Group include: the development of materials, which will be used in the novel semiconductor materials; next generation of photonics and fundamental studies of quantum electronics devices.

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Biomedical Informatics High Power Lasers

Biomedical Informatics research The Photonic and RF Engineering carried out by the Applied Optics Group (PRFEG), based in the Group (AOG), which is based in School of Electrical and Electronic the School of Electrical and Engineering, works closely with Electronic Engineering (EEE), both industry and other research encompass all aspects of the institutes in the area of high power healthcare process ranging from lasers. physiological monitoring, data One of the group’s main areas of encoding and transfer, through to research is in the characterisation biomedical processing and of high power laser . PRFEG data display. In addition, the is able to study the defects and group is part of a virtual centre degradation processes of these developing means of formalising biomedical optics. This includes devices using their custom the assessment of healthcare the development of techniques for designed OMES facility, a robust technology in order to increase the PRFEG is currently researching the spectroscopy of scattering media and highly sophisticated optical efficiency of the medical device degradation processes of single (for example tissue). These new measurement system whose industry. emitters within a laser bar. This techniques are being applied to the characterisation facilities include: has enabled them to define the Previous research has included the design of novel oximeters for long- • photo-/electroluminescence characteristics of a ‘good’ emitter, development of new tools for term ambulatory use. microscopy which is unlikely to degrade and antenatal fetal monitoring, utilising Currently, much effort is also the conditions whereby emitters both the fetal electrocardiogram • spectroscopically-resolved focussed upon the design and are likely to fail. Other work has (recorded transabdominally) and photo-/electroluminescence application of integrated optical revealed the relationship between Doppler ultrasound techniques. microscopy and electronic arrays for soldering induced stress and the The novelty of this data has • micro-photoluminescence use in various forms of biomedical presence of defects in a laser bar. enabled researchers to use microscopy imaging (for example real-time multifractal processing techniques, The group also has a strong full-field laser Doppler flowmetry). • photocurrent spectroscopy developed in-house, to monitor interest in the design and This work is carried out in maturation of the fetal brain • photo-induced current transient modelling of high power lasers. By conjunction with the VLSI design during gestation. spectroscopy working in collaboration with other activities, which are also part of groups, PRFEG has developed • electrical measurements In collaboration with other the Applied Optics Group. experimentally-validated researchers in the Applied Optics Recently the group has also • more traditional measurements, that combines electrical, optical Group, there is also a strong embarked upon collaborative e- e.g. I-V, C-V, L-I and thermal solvers for the research programme in the area of science projects with other Schools modelling of high power lasers. in the University. This has resulted This model is used to investigate in the deployment of remote how design variations in tapered monitoring apparatus in the lasers affect device performance, Antarctic and the development of for example with the addition of advanced ambulatory monitoring beam spoilers and the reduction of the front facet reflectivity. for ‘telemedicine’.

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Materials and Device Characterisation Materials Chemistry

The other expertise pages have The synthesis and characterisation highlighted the vast range of of materials lies at the centre of analysis equipment that exists any materials design strategy. within the University for materials Materials chemistry impacts not and device characterisation, and only on the creation of new the wealth of expertise that is materials and the ways by which • With Physics, new oxide and available to back this up. materials are processed but also nitride semiconductors are being The Advanced Materials Group in on developing the underpinning synthesised and doped with the School of Mechanical, Materials understanding of functionality that appropriate transition metals to and Manufacturing Engineering, drives research forward in new form new dilute ferromagnetic the Photonic and RF Engineering directions. Materials Chemistry semiconductors with potential research in the School of application in spintronics. These Group in the School of Electrical and Electronic Engineering and the Chemistry covers many different materials vary from doped zinc • electron microscopy Semiconductor Physics Group in areas of expertise from solid state oxide and titania to more exotic the School of Physics and • optical microscopy chemistry through polymer and ternary nitrides and from bulk organometallic chemistry to state- Astronomy is home to many of • surface chemical analysis powders to nanostructured thin these analysis and characterisation of-the-art spectroscopy. This films. Using materials chemistry • spectrometry techniques. expertise is applied within the synthetic approaches such as • structural analysis - X-ray and University to address new and sol-gel processing it is possible The key specialisations that are electron diffractometry exciting challenges in Photonics to design new materials of high available within the University and Electronics. homogeneity at a fraction of the include: • scanning probe microscopy Currently, materials chemists are cost required for molecular • thermal analysis engaged in a number of novel and beam epitaxy approaches. • electrical and magnetic topical projects: • With M3, polymers loaded with properties • In work performed with EEE, metallic nanoparticles are being The instrumentation base has new organometallic precursors prepared for potential photonics recently been strengthened by the are being designed for the applications. Key to the award of a new time-of-flight Plasma Enhanced Chemical production of the doped secondary ion mass spectrometry Vapour Deposition (PECVD) polymeric fibres is the use of and XPS instrumentation, which is processing of erbium-doped supercritical fluid processing shared between the Schools of M3, alumina thin films for use as techniques and appropriate Chemistry and Pharmacy. integrated optical . metallic precursors to provide a The ultimate aim is to construct route to novel polymer metal integrated Erbium-doped optical nanocomposites. and loss compensated • Also with M3, new chalcogenide integrated optical circuits. glasses and processing routes are being developed for ultra- low optical loss waveguides and photonic devices.

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Modelling (1) Modelling (2)

Numerical modelling is a diverse • mode matching and integral and significant activity within the equation (IE) methods in both University of Nottingham. Both the time and frequency domains Schools of Electrical and Electronic • general methods for solving Engineering (EEE) and Physics and multi-scale problems Astronomy (Physics) have major modelling activities in the area of These techniques have been used Photonics and Electronics. experimental validation laboratory to address the important issue of enabling it to tackle highly automated design optimisation. School of EEE complex problems. Collaboration with industry on In EEE, the George Green Institute GGIEMR has pioneered the photonic design has led to for Electromagnetics Research development of the Transmission significant technology transfer, a (GGIEMR) covers all areas of Line Modelling (TLM) method since particular example being the electromagnetics research and its the early 1970s, with the most setting up within the GGIEMR of applications. The establishment of research in industry (, recent advances introducing the ‘Bookham Technology Centre this internationally recognised Lucent Technology, USA) and at unstructured meshing into the for Optoelectronic Simulation’ with Institute is strongly supported by the Universities of Yale, Toulouse, technique. Applications of this funding by Bookham Technology the East Midlands Development London (UCL), Paris and Orsay. method include electromagnetic Plc. Other recent collaborations Agency who is funding major compatibility (EMC), microwave include Corning, Coherent Tutcore, Recent work includes studies of infrastructure and personnel to link circuits, antennas, electrical and Nortel, QinetiQ, Alcatel, BAE chaos in semiconductor and optical with industry in the region. thermal modelling of lasers and Systems and Kamelian. devices, which has led to an innovative mechanism for A strong theme of the GGIEMR is semiconductor devices, microwave School of Physics multi-disciplinary work and the heating, field-particle interaction controlling the transmission of In parallel to this activity, the Institute undertakes collaborative and the simulation of transients in electric current through layered Semiconductor Physics (SPG) and work in several important areas. circuits. The GGIEMR also has a periodic semiconductor nano- Theoretical Physics Groups (TPG) Joint projects are in progress with long-standing record for structures. Examples of current in Physics are investigating a wide the Sir Peter Mansfield Magnetic developing novel theory and research are: range of quantum phenomena in Imaging (MRI) Centre numerical techniques for the • manifestations of quantum electronics and photonics. (designing probes for systems that analysis of optical waveguides and chaos in resonant tunnelling will greatly enhance the resolution optoelectronic circuitry. Some of These two groups have extensive • quantum chaotic transport in of present day MRI systems), Life experience of studying quantum the techniques used include: the energy bands of Sciences on EM dosimetry for chaos both experimentally and • the spectral index method (SIM) semiconductor superlattices assessing health risks, Materials theoretically and their work has Engineering (development of novel • the free and half space radiation attracted worldwide interest with • chaotic ray dynamics and EM photonic glasses), mode methods (FSRM, HSRM) presentation in plenary and invited interference in optical fibres (complexity reduction techniques • the finite difference beam talks at international conferences, • fractal resistance in for CAD), and Physics (chaos in propagation method (FD-BPM) and publication in leading scientific microtransistors semiconductor / optical devices). (time and frequency domains) journals, including two cover • quantum chaos for ultra-cold articles in Nature. The work has The Institute has substantial • TLM and Finite Difference Time atoms and Bose-Einstein led to the development of related computational facilities and an Domain (FDTD) methods condensates in optical lattices

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Nanotechnology Nitride Semiconductors

Much of the nanoelectronics and In 1991, the University established nanophotonics research centres an interdisciplinary team for around the Semiconductor Physics research into group III-nitrides Group (SPG) in the School of and now has an internationally Physics and Astronomy (Physics). recognised leading position in this This group works closely with both field. Based in the PRFEG in EEE the Nanoscience and Theoretical and the SPG in Physics, this team Physics Groups – also in Physics – developed the first plasma- and other research groups within industrial applications in stable assisted molecular beam epitaxy the University and elsewhere. lasers with low-threshold currents. (PA-MBE) growth facilities together with associated characterisation Quantum dots are boxes with Quantum dots also raise exciting dimensions of a few nanometres. facilities for group III-nitrides in acceptor in GaN. The Nottingham fundamental questions about Europe. team has also: Currently, there is considerable condensed matter and many-body interest in semiconducting ‘self- physics. To explore these The SPG is responsible for the • studied strain relaxation assembled’ dots and researchers questions, researchers are now growth of nitride semiconductors processes in AlGaN/GaN have established a major research investigating the electronic states and the structural assessment of heterostructures programme to investigate novel of model pyramidal dots in a the films using X-ray diffraction. • investigated the surface fabrication techniques and the quantizing magnetic field. More Meanwhile, PRFEG concentrates on reconstruction of homoepitaxial electrical and optical properties of realistic models which include the the opto-electrical characterisation GaN such structures. Uniquely, this of these materials as well as effects of strain and material • characterised cubic and work includes the use of phonon composition on the electronic band device fabrication. In addition, spectroscopy. structural characterisation of hexagonal GaN using Raman structure will be used to interpret spectroscopy In collaboration with research experimental results and explore semiconductors and contacts is groups at the Universities of ways to obtain improved radiative undertaken in the AMG based in In collaboration with Sharp Labs of Cardiff and Sheffield, the SPG has efficiencies in laser diodes. the School of M3. Europe, the team was one of the first in Europe to demonstrate a produced semiconductor quantum One of the ultimate aims in the Working together with UNIPRESS, dot lasers comparable with the Nottingham has demonstrated the UV light emitting . The team's field of functional nanotechnology most recent achievements are the best in the world. Such structures is to form electrical contact to a advantages of growth on bulk have considerable potential for gallium nitride (GaN) substrates, demonstration of strong blue one-dimensional wire of atoms or photoluminescence (PL) at room molecules, or even an individual growing dislocation free films of GaN and AlGaN/GaN multi- from isoelectronically molecule. One approach used at doped GaN and p-type cubic the University of Nottingham quantum well structures. Building upon this experience, UNIPRESS GaMnN for spintronic applications. involves forming nanostructures As part of a new Basic Technology using an STM tip between doped have recently announced the first blue/UV made by PA-MBE. The grant, we are now growing contacts on silicon samples. 15 team has made many significant hyperpolarizing GaN with N, for Researchers have also developed a efficient transfer of spins to UHV prober to investigate the contributions to understanding the problems involved in p-doping with organic and biological overlayer electrical characteristics of the species. nanostructures. Mg in GaN and have discovered a new, as yet unidentified, shallow

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Novel Photonic Glasses Optical Engineering

Novel glasses can exhibit much The Applied Optics Group (AOG) in greater optical versatility than the School of Electrical and conventional high silica glass. Electronic Engineering (EEE), is Properties of these glasses developing a range of advanced include: a wide refractive index optical microscopy systems to range; flexibility in wavelength probe previously inaccessible compatibility; low phonon energy properties of a range of surfaces and non-linear optical behaviour, and materials. making them ideal for applications The main research areas of AOG such as new generation all-optical are microscopy, laser ultrasonics and hot spin casting of thin films micro-amplifiers and integrated and optical scattering. Examples of and an optical darkroom for sources, switches and and research activities include: for infrared power delivery. assessing performance. Potential applications include: The Group has also attracted • non-contact acoustic microscopy (O-SAM) substantial research funding from • telecoms • optical sensors for transdermal government agencies and industry • high speed interferometric infrared communications drug delivery systems • including: EPSRC; The Royal microscopy for dynamic process • environmental monitoring Society; Dstl; Qinetiq; Dow measurements • polarisation techniques for skin thickness measurements • medical diagnostics Corning; Nortel Networks, and • ultrastable common path Bookham Technology for the The group has also developed a • power delivery for laser surgery microscopy using development of chalcogenide, generated holograms whole suite of techniques based on The Novel Photonic Glasses halide and heavy metal oxide the Surface Plasmon Resonance • high NA electronic speckle Research Group in the School of based glasses and transparent phenomenon. Surface plasmons pattern interferometer M3 has recently commissioned nano-structured glass-ceramics. are electromagnetic waves that world class facilities for the The Group works closely with the • optical phased arrays for propagate along the interface making, shaping and testing of George Green Institute for imaging heavily scattering between a thin metal layer and a novel glass fibre and planar Electromagnetics Research in the media dielectric. Their importance as waveguides and bulk glass optical School of Electrical and Electronic • SMART optical microscope using chemical and biosensors lies in the components. Facilities include: Engineering for the modelling and spatial light modulator fact that these methods are controlled atmosphere; dedicated designing of devices. extremely sensitive to dielectric gloveboxes for clean glass melting; The lithographic patterning of properties of the material, which is a class 10,000 cleanroom integrated glass waveguides is in contact with the metal layer. fabrication laboratory for optical being conducted in collaboration This patented technique can give fibre drawing, extrusion, pressing with the Semiconductor Physics high-resolution images of a variety Group in the School of Physics and of surfaces based on differences in Astronomy. Development of new dielectric constant. glass precursors, and alternative Fluorescence can be measured or processes to glass melting, is induced to provide a spatial map of carried out in collaboration with the activity and functionality of the School of Chemistry. biological samples.

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Power Electronics RF Circuits and Systems

Power Electronics involves the RF circuits and systems are an control and processing of electrical essential part of todays mobile energy using power semiconductor society. A vision of the future sees switching devices. It is an enabling a convergence between mobile technology with applications from communication and entertainment >1W - GW. The Power Electronics, fuelled by the freedom of wireless Machines and Control Group at the networking (i.e. a mobile phone University of Nottingham has a will have a broadband internet large research team (>50) working connection making it also a with industry including, Boeing, US versatile audio and video player).

Army Research Laboratories, e2v The Photonic and Frequency recently awarded the status of a Technologies, Smiths , Engineering Group (PRFEG) in the Marie Curie Training Centre by the Areva and DSTL for example. School of Electrical and Electronic EU. The Group’s activities range from Engineering (EEE) have significant consultative, feasibility and In power electronics, the Groups research activities in the design evaluation studies for industry activities are focussed on: Direct and characterisation of RF circuits bit error rate testing (BERT) of through to blue-sky research. It AC-AC Power Converters, Multi- and systems. electronic and photonic circuits. has a well-equipped modelling level and Multi-Cellular Converters The University has recently made Some of our research is being laboratory supporting all the major (very high power applications), significant investments in new undertaken in collaboration with software suites. However, one of Power Supplies for High Power RF equipment for continued research the Applied Optics Group (AOG), the distinguishing features of the Applications and Power in this area. With the most recent also in EEE, and Semiconductor Group is its ability to carry out Converter/ integration. acquisitions, we are now able to Physics Group (SPG) in the School both pure and applied research at Other activities of the Group measure devices and circuits using of Physics. real power levels and this has include: Sensorless AC drive the new vector network analyser Some of our current research attracted industrial support and control, Motor drive efficiency and up to 330 GHz, with on wafer projects include: funding which have allowed the instrumentation methods, Robust measurements being possible up Group to expand their operations control, System control of wind to 240GHz. The new equipment • Ultra wideband radiolocation to 1MW (continuous). This fact was and hybrid generation, EMC in also provides the ability to perform • High frequency CMOS and instrumental in the Group being drives and power electronic BiCMOS phase lock loops systems • Investigation of sub-millimetre Nearly all the Group’s projects are wavelength devices either completely or partially supported by industry. The Group • Radio over fibre has a good record of transferring • Dielectric constant the outcomes of its research into measurement of ceramics industry through collaborative • High speed photonic circuits research and through Teaching Company Schemes and Knowledge • System performance in the presence of signal impairments Transfer Partnerships.

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Spintronics VLSI Design

Semiconductor spintronics is an The VLSI Design activity of the emerging field that aims to Applied Optics Group (AOG) in the integrate the functionality of School of EEE has state-of-the-art semiconductor and magnetic CAD facilities and renowned materials to deliver new types of expertise in the design, fabrication devices for information storage and characterisation of CMOS and and processing. The spintronics Bipoloar VLSI systems, which research activity at Nottingham is includes access to SiGe foundries. carried out by a large team based Recently, researchers in the group in the Schools of Physics, EEE, M3 capacitance microscopy system is also available. have been combining an array of and Chemistry. Current industrial photodetectors with on-chip CMOS collaborations include Qinetiq, Currently, the University is the VLSI processing onto a single piece Hitachi, Sharp and Seagate. only source of III-V ferromagnetic of silicon to form a ‘smart’ optical The interdisciplinary team has a semiconductors in the UK. processor. Working with other range of growth, fabrication and Recent successes include: researchers in the AOG, this Additional VLSI research interests characterisation facilities available, method has been applied to the • the growth of GaMnAs material in the group include: including photoluminescence (PL), development of a single-chip laser with world record Curie • low-cost inertial sensors for scanning tunnelling microscopy Doppler flowmetry system for (173K) physiological monitoring (STM), atomic and magnetic force vascular blood flow (and other microscopy (AFM/MFM) and X-ray • ferromagnetic TiCoO2 and p- fluid flow analysis), a full-field • object location using a radio and TEM facilities for structural type GaMnN, which show surface plasmon resonance imager frequency analysis. ferromagnetism at room for bioassays, photoacoustic arrays • field programmable gate arrays temperature for the detection of surface More advanced magneto-transport • integrated VLSI sensors for RF aberrations, ultrasound modulated facilities include a range of A characteristic of the GaMnAs leadless applications cryomagnetic systems (magnetic layers grown by the team is their laser tomography for tumour • ASIC's for electrophysiological fields up to 18.5T, temperatures low resistivity that is accompanied location and other modulated light recorders down to 5mK and hydrostatic by very weak high field magneto- camera applications. pressures up to 8 Kbar). A low resistance. This has enabled temperature (1K), high magnetic researchers to separate the normal field (12T) AFM / MFM / scanning and anomalous contributions to the Hall effect and make the first accurate measurements of hole densities across a range of manganese compositions. Using this new information the first meaningful comparisons of the theoretically predicted Curie temperatures and extraordinary Hall conductivities with experiment have been made.

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Key Research Groups

School of Chemistry (Chemistry) www.nottingham.ac.uk/chemistry Solid State and Materials Chemistry Group

School of Electrical and Electronic Engineering (EEE) www.nottingham.ac.uk/eee Applied Optics Group (AOG) George Green Institute for Electromagnetics Research (GGIEMR) Photonic and RF Engineering Group (PRFEG) Power Electronics, Machines and Control Group (PEMC) Ultrasonics and Nondestructive Evaluation Group (UNDEG)

School of Physics and Astronomy (Physics) www.nottingham.ac.uk/physics Nanoscience Group Semiconductor Physics Group (SPG) Theoretical Physics Group (TPG)

School of Mechanical, Materials and Manufacturing Engineering (M3) www.nottingham.ac.uk/schoolm3 Advanced Materials Group (AMG)

Interdisciplinary Units IDTC for Photonics and Electronics www.nottingham.ac.uk/p-e Nottingham Nanotechnology Centre (NNC) www.nottingham.ac.uk/nano University of Nottingham Institute for Materials Technology (UNIMAT) www.nottingham.ac.uk/unimat

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