Dr Duncan Allsopp
BSc, MSc, PhD, MIEEE, MInst. Phys. C.Phys.
Profile
Dr Allsopp received the degrees of BSc in Physics, MSc and PhD in Electronic Engineering from the University of Sheffield in 1971, 1974 and 1977. From 1977 to 1979 he was at Ferranti Electronics Limited developing high speed Si transistors and integrated circuits.
From 1979 to 1984 he was at UMIST researching defects in semiconductors, and from 1984 to 1986 he was at British Telecom Research Laboratories, Martlesham Heath.
In 1986 he joined the University of York where he established a group researching photonic devices. In 1999 he joined the Optoelectronics Group at the University of Bath.
For 2006-2007 he was Royal Academy of Engineering/ Leverhulme Trust Senior Research Fellow researching nanofabrication technologies for photonic applications.
Research
- GaN Light Emitting Diodes for solid state lighting
This collaborative research project funded by the DTI involves advancing LED performance. The research exploits the University’s capability to grow state-of-the-art Group III-Nitride epitaxy by MOVPE and HVPE, its facilities nanofabrication and advanced optoelectronic device characterisation. - Novel nanofabrication techniques and their application to sub-wavelength optical devices and to advanced Group III-Nitride epitaxial growth (funded by the European Union FP 6 STREP “N2T2”)
- Advanced optical modulators and switches based quantum well effects (EPSRC funded).
This research has two strands: an investigation of the application of electroabsorption modulators to the generation and detection of TeraHertz radiation and of the feasibility of using intersubband absorption to high speed optical modulation. - Sensors and electronics for harsh environments (EU funded via FP7)
This project will exploit the properties of c-plane GaN for sensing pressure, mechanical force and temperature in harsh environments, including high temperatures (above 500°C). The research includes developing GaN epitaxial growth on Si/polycrystalline diamond composite substrates designed for heat extraction and/or thermal stability. Other sensor research includes developing wide area arrays of sensors for robotic skin (supported by OCRobotics, Bristol).
Teaching
- Electronic Devices and Circuits
- Communications Principles
- Electronics for the Space Environment
- Optical Communications Systems
Publications
Book Sections
Silver, J., Yan, X., Withnall, R., Fern, G., Sumner, J., Shields, P. and Allsopp, D., 2011. Embedding manganese doped zinc sulfide quantum dots in gallium nitride LEDs based on photonic crystals. In: Proceedings of the International Display Workshops. Vol. 3. , pp. 1405-1408.
Withnall, R., Silver, J., Catherall, C., Ireland, T.G., Fern, G.R., Sumner, J.W.S., Shields, P., Allsopp, D., Reip, P.W. and Subbiah, S., 2011. Incorporating cerium doped yttrium aluminium garnet (YAG:Ce) nanophosphors into gallium nitride LEDs based on photonic crystals. In: Proceedings of the International Display Workshops. Vol. 3. , pp. 1413-1416.
Edwards, M. J., Vittoz, S., Amen, R., Rufer, L., Johander, P., Bowen, C. R. and Allsopp, D. W. E., 2010. Modelling and optimisation of a sapphire/GaN-based diaphragm structure for pressure sensing in harsh environments. In: Conference Proceedings - The 18th International Conference on Advanced Semiconductor Devices and Microsystems, ASDAM 2010. Piscataway, NJ: IEEE Computer Society, pp. 127-130.
Liu, C., Wang, W. N., Shields, P. A., Denchitcharoen, S., Causa, F. and Allsopp, D. E. W., 2008. Improvement of efficiency droop in resonanace tunneling LEDS. In: Ferguson, I. T., Taguchi, T., Ashdown, I. E. and Park, S. J., eds. 8th International Conference On Solid State Lighting. Vol. 7058. Spie-Int Soc Optical Engineering, D580-D580. (Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE))
Zhang, J. Z. and Allsopp, D., 2008. Wavelength Conversion by Terahertz Electro-Optic Modulation in Asymmetric Coupled Quantum Wells. In: 2008 Conference on Lasers and Electro-Optics & Quantum Electronics and Laser Science Conference. New York: IEEE, pp. 2780-2781.
Articles
Zhuang, Y.D., Lewins, C.J., Lis, S., Shields, P.A. and Allsopp, D.W.E., 2013. Fabrication and characterization of light-emitting diodes comprising highly ordered arrays of emissive InGaN/GaN nanorods. IEEE Photonics Technology Letters, 25 (11), pp. 1047-1049.
Zhuang, Y. D., Lis, S., Bruckbauer, J., O'Kane, S. E. J., Shields, P. A., Edwards, P. R., Sarma, J., Martin, R. W. and Allsopp, D. W. E., 2013. Optical properties of GaN nanorods containing a single or multiple InGaN quantum wells. Japanese Journal of Applied Physics, 52, 08JE11.
Le Boulbar, E.D., Edwards, M.J., Vittoz, S., Vanko, G., Brinkfeldt, K., Rufer, L., Johander, P., Lalinský, T., Bowen, C.R. and Allsopp, D.W.E., 2013. Effect of bias conditions on pressure sensors based on AlGaN/GaN High Electron Mobility Transistor. Sensors and Actuators A-Physical, 194, pp. 247-251.
Lewins, C.J., Allsopp, D.W.E., Shields, P.A., Gao, X., Humphreys, B. and Wang, W.N., 2013. Light extracting properties of buried photonic quasi-crystal slabs in InGaN/GaN LEDs. IEEE/OSA Journal of Display Technology, 9 (5), pp. 333-338.
Chan, C.C.S., Reid, B.P.L., Taylor, R.A., Jia, W., Zhuang, Y. D., Shields, P.A. and Allsopp, D.W.E., 2013. Optical studies of the surface effects from the luminescence of single GaN/InGaN nanorod light emitting diodes fabricated on a wafer scale. Applied Physics Letters, 102 (11), 111906.
Priesol, J., Šatka, A., Uherek, F., Donoval, D., Shields, P. and Allsopp, D.W.E., 2013. Quantitative analysis of cathodoluminescence phenomena in InGaN/GaN QW by Monte Carlo method. Applied Surface Science, 269, pp. 155-160.
Huang, C.-N., Shields, P. A., Allsopp, D. W.E. and Trampert, A., 2013. Forthcoming. Coalescence-induced planar defects in GaN layers grown on ordered arrays of nanorods by metal–organic vapour phase epitaxy. Philosophical Magazine
Edwards, P.R., Jagadamma, L.K., Bruckbauer, J., Martin, R.W., Liu, C., Shields, P., Allsopp, D. and Wang, T., 2012. High-resolution cathodoluminescence hyperspectral imaging of nitride nanostructures. Microscopy and Microanalysis, 18 (6), pp. 1212-1219.
Hubbard, G., Nasir, M. E., Shields, P., Bowen, C. R., Satka, A., Parsons, K. P., Holmes, N. H. and Allsopp, D. W. E., 2012. Angle dependent optical properties of polymer films with a biomimetic anti-reflecting surface replicated from cylindrical and tapered nanoporous alumina. Nanotechnology, 23 (15), 155302.
Shields, P. A., Charlton, M. D. B., Lewins, C. J., Gao, X., Allsopp, D. W. E., Wang, W. N. and Humphreys, B., 2012. Effect of coalescence layer thickness on the properties of thin-chip InGaN/GaN light emitting diodes with embedded photonic quasi-crystal structures. Physica Status Solidi (A), 209 (3), pp. 451-455.
Shields, P., Hugues, M., Zúñiga-Pérez, J., Cooke, M., Dineen, M., Wang, W., Causa, F. and Allsopp, D., 2012. Fabrication and properties of etched GaN nanorods. Physica Status Solidi (C) Current Topics in Solid State Physics, 9 (3-4), pp. 631-634.
Jiang, Q., Edwards, M. J., Shields, P. A., Allsopp, D. W. E., Bowen, C. R., Wang, W. N., Tóth, L., Pécz, B., Srnanek, R., Satka, A. and Kovac, J., 2012. Growth of crack-free GaN epitaxial thin films on composite Si(111)/polycrystalline diamond substrates by MOVPE. Physica Status Solidi (C) Current Topics in Solid State Physics, 9 (3-4), pp. 650-653.
Chan, C. C. S., Shields, P. A., Holmes, M. J., Zhuang, Y., Wang, X., Reid, B. P. L., Kim, H., Allsopp, D. W. E. and Taylor, R. A., 2012. Optical studies of quantum dot-like emission from localisation centres in InGaN/GaN nanorod array LEDs. Physica Status Solidi (C) Current Topics in Solid State Physics, 9 (3-4), pp. 635-638.
Edwards, M. J., Le Boulbar, E. D., Vittoz, S., Vanko, G., Brinkfeldt, K., Rufer, L., Johander, P., Lalinský, T., Bowen, C. R. and Allsopp, D. W. E., 2012. Pressure and temperature dependence of GaN/AlGaN high electron mobility transistor based sensors on a sapphire membrane. Physica Status Solidi (C) Current Topics in Solid State Physics, 9 (3-4), pp. 960-963.
Hicks, M.-l., Tabeart, J., Edwards, M. J., Le Boulbar, E. D., Allsopp, D. W. E., Bowen, C. R. and Dent, A. C. E., 2012. High temperature measurement of elastic moduli of (0001) gallium nitride. Integrated Ferroelectrics, 133 (1), pp. 17-24.
Lewis, R. W. C., Allsopp, D. W. E., Shields, P., Šatka, A., Yu, S., Topolov, V. Y. and Bowen, C. R., 2012. Nano-Imprinting of Highly Ordered Nano-Pillars of Lithium Niobate (LiNbO3). Ferroelectrics, 429 (1), pp. 62-68.
Lewis, R. W. C., Bowen, C. R., Topolov, V. Y. and Allsopp, D. W. E., 2012. Role of Single-Crystal Pillars in Forming the Effective Properties and Figures of Merit of Novel 1–3 Piezocomposites. Integrated Ferroelectrics, 133 (1), pp. 103-108.
Lethy, K.J., Edwards, P.R., Liu, C., Shields, P.A., Allsopp, D.W.E. and Martin, R.W., 2012. Cathodoluminescence studies of GaN coalesced from nanopyramids selectively grown by MOVPE. Semiconductor Science and Technology, 27 (8), 085010.
Regonini, D., Satka, A., Jaroenworaluck, A., Allsopp, D. W. E., Bowen, C. R. and Stevens, R., 2012. Factors influencing surface morphology of anodized TiO 2 nanotubes. Electrochimica Acta, 74, pp. 244-253.
Shields, P. A. and Allsopp, D. W. E., 2011. Nanoimprint lithography resist profile inversion for lift-off applications. Microelectronic Engineering, 88 (9), pp. 3011-3014.
Shields, P., Liu, C., Atka, A., Trampert, A., Zuniga-Perez, J., Alloing, B., Hako, D., Uherek, F., Wang, W., Causa, F. and Allsopp, D., 2011. Nanopendeo coalescence overgrowth of GaN on etched nanorod array. Physica Status Solidi (C) Current Topics in Solid State Physics, 8 (7-8), pp. 2334-2336.
Wang, W. N., Shields, P. A., Liu, C., Allsopp, D. W. E. and Causa, F., 2011. Advances in nano-enabled GaN photonic devices. Proceedings of SPIE - The International Society for Optical Engineering, 7945, 794523.
Edwards, M. J., Bowen, C. R., Allsopp, D. W. E. and Dent, A. C. E., 2010. Modelling wafer bow in silicon-polycrystalline CVD diamond substrates for GaN-based devices. Journal of Physics D: Applied Physics, 43 (38), 385502.
Charlton, M. D. B., Shields, P. A., Allsopp, D. W. E. and Wang, W., 2010. High-efficiency photonic quasi-crystal light emitting diodes incorporating buried photonic crystal structures. Proceedings of SPIE - The International Society for Optical Engineering, 7784, 778407.
Nasir, M. E., Allsopp, D. W. E., Bowen, C. R., Hubbard, G. and Parsons, K. P., 2010. The fabrication of mono-domain highly ordered nanoporous alumina on a wafer scale by a guided electric field. Nanotechnology, 21 (10), 105303.
Liu, C., Shields, P., Chen, Q., Allsopp, D., Wang, W. N., Bowen, C., Phan, T. l. and Cherns, D., 2010. Variations in mechanisms of selective area growth of GaN on nano-patterned substrates by MOVPE. Physica Status Solidi (C) Current Topics in Solid State Physics, 7 (1), pp. 32-35.
Zhang, J. Z. and Allsopp, D., 2009. Strong-field terahertz optical sideband generation for wavelength conversion in asymmetric double quantum wells. Applied Physics Letters, 95 (23), 231916.
Zhang, J. Z. and Allsopp, D., 2009. Excitonic absorption in asymmetric double quantum wells in an intense terahertz field: Coulombic coupling and Stark effects. Physical Review B, 80 (24), 245320.
Liu, C., Satka, A., Jagadamma, L. K., Edwards, P. R., Allsopp, D., Martin, R. W., Shields, P., Kovac, J., Uherek, F. and Wang, W. N., 2009. Light emission from InGaN quantum wells grown on the facets of closely spaced GaN nano-pyramids formed by nano-imprinting. Applied Physics Express, 2 (12), 121002.
Shields, P. A., Liu, C., Nasir, M., Allsopp, D. W. E. and Wang, W. N., 2009. Enhanced light extraction in nitride light-emitting diodes by epitaxially grown photonic-crystal nanopyramid arrays. Applied Physics Letters, 95 (12), 123120.
Regonini, D., Satka, A., Allsopp, D. W. E., Jaroenworaluck, A., Stevens, R. and Bowen, C. R., 2009. Anodised titania nanotubes prepared in a glycerol/NaF electrolyte. Journal of Nanoscience and Nanotechnology, 9 (7), pp. 4410-4416.
Shields, P. A., Charlton, M. D. B., Lee, T., Zoorob, M. E., Allsopp, D. W. E. and Wang, W. N., 2009. Enhanced light extraction by photonic quasi-crystals in GaN blue LEDs. IEEE Journal of Selected Topics in Quantum Electronics, 15 (4), pp. 1269-1274.
Chen, Q., Hubbard, G., Shields, P. A., Liu, C., Allsopp, D. W. E., Wang, W. N. and Abbott, S., 2009. Broadband moth-eye antireflection coatings fabricated by low-cost nanoimprinting. Applied Physics Letters, 94 (26), 263118.
Chen, Q. and Allsopp, D. W. E., 2009. Group velocity delay in coupled-cavity waveguides based on ultrahigh-Q cavities with Bragg reflectors. Journal of Optics A: Pure and Applied Optics, 11 (5), 054010.
Hubbard, G., Abbott, S. J., Chen, Q., Allsopp, D. W. E., Wang, W. N., Bowen, C. R., Stevens, R., Satka, A., Hasko, D., Uherek, F. and Kovac, J., 2009. Wafer-scale transfer of nanoimprinted patterns into silicon substrates. Physica E-Low-Dimensional Systems & Nanostructures, 41 (6), pp. 1118-1121.
Chen, Q., Archbold, M. D. and Allsopp, D. W. E., 2009. Design of ultrahigh-Q 1-D photonic crystal microcavities. IEEE Journal of Quantum Electronics, 45 (3), pp. 233-239.
Chen, Q. and Allsopp, D. W. E., 2009. Design of tapering one-dimensional photonic crystal ultrahigh-Q microcavities. Photonics and Nanostructures - Fundamentals and Applications, 7 (1), pp. 19-25.
Wong, K. M. and Allsopp, D. W. E., 2009. Intersubband absorption modulation in coupled double quantum wells by external bias. Semiconductor Science and Technology, 24 (4), 045018.
Drzik, M., Satka, A., Hasko, D., Kovac, J., Uherek, F., Allsopp, D. W. P., Abbott, S. J. and Hubbard, G., 2008. Large area diffraction-based inspection of submicron periodic structures. Microelectronic Engineering, 86 (4-6), pp. 1025-1028.
Jaroenworaluck, A., Regonini, D., Bowen, C. R., Stevens, R. and Allsopp, D., 2007. Macro, micro and nanostructure of TiO2 anodised films prepared in a fluorine-containing electrolyte. Journal of Materials Science, 42 (16), pp. 6729-6734.
Xiaohua, S., Wei, D. and Allsopp, D. W. E., 2007. Multiwavelength Transmission Microcavity in SOI Planar Ridge Waveguides. Journal of Lightwave Technology, 25 (8), pp. 2206-2212.
Zhou, L. and Allsopp, D. W. E., 2005. Wavelength conversion in electroabsorption modulators by cross-bias modulation. Electronics Letters, 41 (9), pp. 556-557.
Chen, X., Allsopp, D. W. E. and Batty, W., 2004. Transition from two-dimensional to three-dimensional electroabsorption in extremely shallow quantum wells. Semiconductor Science and Technology, 19 (2), pp. 263-269.
Kaduki, K. A., Ghiti, A., Batty, W. and Allsopp, D. W. E., 2003. Reduced threshold current in bipolar diode lasers by non-square quantum well growth. Physica Scripta, 67 (1), pp. 68-73.
Yunus, K., Marks, C. B., Fisher, A. C., Allsopp, D. W. E., Ryan, T. J., Dryfe, R. A. W., Hill, S. S., Roberts, E. P. L. and Brennan, C. M., 2002. Hydrodynamic voltammetry in microreactors: multiphase flow. Electrochemistry Communications, 4 (7), pp. 579-583.
Earnshaw, M. and Allsopp, D., 2002. Semiconductor space switches based on multimode interference couplers. IEEE Journal of Lightwave Technology, 20, pp. 643-650.
Earnshaw, M. P. and Allsopp, D. W. E., 2001. Electrooptic effects in GaAs-AlGaAs narrow coupled quantum wells. IEEE Journal of Quantum Electronics, 37 (7), pp. 897-904.
Yunus, K., Rickson, S. A., Fisher, A. C., Henley, I. E., Allsopp, D. W. E. and Ryan, T. J., 2001. Flow visualisation: a voltammetric approach. Electrochemistry Communications, 3 (8), pp. 455-459.
Chen, X., Batty, W., Earnshaw, M. and Allsopp, D., 2001. The role of Coulombic coupling in electroabsorption in square quantum wells. Semiconductor Science and Technology, 16, pp. 455-459.
Conference or Workshop Items
Jackson, A., Allsopp, D. and Walsh, A., 2011. Oxidation of GaN for light conversion: Ab initio thermodynamic modelling. In: RSC Solid State Chemistry Group Christmas Meeting 2011, 2011-12-19 - 2011-12-20, Liverpool.
Jackson, A., Allsopp, D. and Walsh, A., 2011. LED lighting: oxidation of GaN from ab initio thermodynamic modelling. In: DTC Summer Showcase 2012, 2012-07-09 - 2013-04-13, Bath.
Shields, P. A., Chan, C., Read, N., Allsopp, D. W. and Taylor, R. A., 2010. Photoluminescence and Electroluminescence in InGaN/GaN Nano-Rod Array LEDs Fabricated on a Wafer Scale. In: Solid-State and Organic Lighting (SOLED), 2010-06-21, Karlsruhe.
Shields, P.A., Lis, S., Lee, T., Allsopp, D.W.E., Charlton, M.D.B., Zoorob, M.E. and Wang, W.N., 2009. Influence of guided mode absorption on the effectiveness of GaN-on-sapphire photonic crystal light-emitting diodes. In: Conference on Lasers and Electro-Optics, 2009 and 2009 Conference on Quantum electronics and Laser Science Conference, 2009-06-02 - 2009-06-03, Baltimore, M.D..
Zhang, J. and Allsopp, D., 2007. Generation of Terahertz sidebands in coupled quantum wells. In: Terahertz Photonics Meeting, 2007-01-01, Leeds.
Wong, K. M. and Allsopp, D. W. E., 2007. Modelling Intersubband Electroabsorption Modulation. In: Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2007), 2007-05-06 - 2007-05-11, Baltimore, MD.
Allsopp, D., Henning, I., Seeds, A. and Linfield, E., 2007. PORTRAIT: Portable Terahertz systems based on advanced InP technology. In: Terahertz Photonics Meeting, 2007-01-01, Leeds.
Shi, X., Ding, W. and Allsopp, D., 2007. SOI ridge waveguide incorporating a photonic crystal microcavity multi-transmission filter. In: Conference on Lasers and Electro-optics, 2007-05-06 - 2007-05-11, Baltimore, U.S.A.
Bowen, C., Allsopp, D., Stevens, R., Shields, P. and Wang, W., 2006. Modelling and designing GaN piezeoelectric MEMS,. In: Second International Conference on Multi-Material Micro Manufacture, 2006-01-01, Grenoble.
Allsopp, D., 2005. GaN: Materials properties, processing and applications," Invited talk at the Fall Meeting of the Ceramics Cluster of the Multi-Material Micro Manufacture. In: Network of Excellence, 2005-01-01, Gothenburg.
Woods, S., Walker, A., Stern, M. and Allsopp, D., 2003. Analysis of heterojunction phototransistors. In: Invited contribution to Workshop on Heterojunction Phototransistors, 2003-01-01, Budapest.
Allsopp, D., Bhatnagar, A., Earnshaw, M. and Chen, X., 2002. Quantum well and superlattice design for super-efficient optical modulation. In: Photon’02, 2002-01-01, Cardiff.
Earnshaw, M. and Allsopp, D., 2001. Optical space switching by selective mode perturbation in semiconductor multimode interferometers. In: Semiconductor and Integrated Optoelectronics Conference, SIOE, 2001-01-01, Cardiff.
Allsopp, D., Earnshaw, M. and Bhatnagar, A., 2001. Potential of AlGaAs/GaAs coupled narrow quantum wells for optical phase modulation. In: Semiconductor and Integrated Optoelectronics Conference, 2001-01-01, Cardiff.
Chen, X., Batty, W. and Allsopp, D., 2001. The influence of Coulombic coupling on the quantum confined Stark Effect. In: Semiconductor and Integrated Optoelectronics Conference, SIOE, 2001-01-01, Cardiff.
Patent
Timothy Peter, Mollart, 2012. Diamond composite substrate for semiconductor devices. H01L21/02-GB2481687 (A), 04 January 2012.
