Dr Paul Edwards

Senior Research Fellow

Physics

Personal statement

I am a Senior Research Fellow in the Department of Physics, where I have worked in the Semicondcutor Spectroscopy and Devices research group since 2000. Prior to this, I studied at Imperial College London, Albert Ludwigs Universität Freiburg and Durham University. My PhD and post-doctoral work at Durham involved the use of scanning electron and optical beam techniques to study thin-film CdTe solar cells. I now apply similar techniques to characterise materials, nanostructures and devices made from group III nitride compounds.

Researcher ID: C-1594-2009

ORCID ID: 0000-0001-7671-7698

| e: paul.edwards@strath.ac.uk | t: 0141 548 4369/3488/7917 | u: http://ssd.phys.strath.ac.uk/ |

Publications

Spatially-resolved optical and structural properties of semi-polar (11-22) AlxGa1-xN with x up to 0.56
Bruckbauer Jochen, Li Zhi, Gunasekar Naresh, Warzecha Monika, Edwards Paul R., Jiu Ling, Bai Jie, Wang Tao, Trager-Cowan Carol, Martin Robert W.
Scientific Reports Vol 7, (2017)
http://dx.doi.org/10.1038/s41598-017-10923-9
Quantum well engineering in InGaN/GaN core-shell nanorod structures
Bryce C. G., Le Boulbar E. D., Coulon P.-M., Edwards P. R., Gîrgel I., Allsopp D. W. E., Shields P. A., Martin R. W.
Journal of Physics D: Applied Physics, (2017)
Charge carrier localised in zero-dimensional (CH3NH3)3Bi2I9 clusters
Ni Chengsheng, Hedley Gordon J., Payne Julia, Svrcek Vladimir, McDonald Calum, Jagadamma Lethy Krishnan, Edwards Paul, Martin Robert, Mariotti Davide, Maguire Paul, Samuel Ifor, Irvine John
Nature Communications Vol 8, (2017)
http://dx.doi.org/10.1038/s41467-017-00261-9
Influence of the copper content on the optical properties of CZTSe thin films
Yakushev M. V., Sulimov M. A., Márquez-Prieto J., Forbes I., Krustok J., Edwards P. R., Zhivulko V. D., Borodavchenko O. M., Mudryi A. V., Martin R. W.
Solar Energy Materials and Solar Cells Vol 168, pp. 69-77, (2017)
http://dx.doi.org/10.1016/j.solmat.2017.04.022
Analysis of doping concentration and composition in wide bandgap AlGaN:Si by wavelength dispersive X-ray spectroscopy
Kusch Gunnar, Mehnke Frank, Enslin Johannes, Edwards Paul R, Wernicke Tim, Kneissl Michael, Martin Robert W
Semiconductor Science and Technology Vol 32, (2017)
http://dx.doi.org/10.1088/1361-6641/aa58cf
Hysteretic photochromic switching of Eu-Mg defects in GaN links the shallow transient and deep ground states of the Mg acceptor
Singh A. K., O'Donnell K. P., Edwards P. R., Lorenz K., Kappers M. J., Bokowski M.
Scientific Reports Vol 7, (2017)
http://dx.doi.org/10.1038/srep41982

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Research interests

My research is focussed on the use of spectroscopic and microscopic methods in the analysis of semiconductors. The main materials of current interest to me are those based on the group III nitride quaternary system, AlxGayIn(1-x-y)N, and in particular nano-scale structures based on them. These have applications in many different areas, including solid-state lighting, data storage, communications and water purification. The techniques I use to study these materials include photoluminescence and electroluminescence spectroscopy, as well multiple modes of scanning electron microscopy (such as cathodoluminescence, electron beam-induced current and X-ray microanalysis). I am also interested in the application of multivariate statistical analysis techniques in the processing of the multidimensional data that these experimental methods yield.

Professional activities

12th International Conference on Nitride Semiconductors (ICNS-12)
Participant
23/7/2017
Microscience Microscopy Congress (MMC2015)
Invited speaker
2/7/2015
13th Australian Microbeam Analysis Symposium
Invited speaker
12/2/2015
13th Australian Microbeam Analysis Symposium
Invited speaker
9/2/2015
John Anderson Research Colloquium
Invited speaker
29/10/2014
2014 UK Optical Designers' Meeting
Participant
25/9/2014

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Projects

Light-controlled manufacturing of semiconductor structures: a platform for next generation processing of photonic devices
Skabara, Peter (Principal Investigator) Dawson, Martin (Co-investigator) Edwards, Paul (Co-investigator) Martin, Robert (Co-investigator) Watson, Ian (Co-investigator)
"This Platform Grant (PG) will apply our internationally-leading expertise in structured illumination and hybrid inorganic/organic semiconductor optoelectronic devices to create new opportunities in the rapidly developing field of light-controlled manufacturing. Structured illumination fields can in principle be obtained from both inorganic (GaN) and organic LEDs, implemented on a macroscale via relay optics, or demagnified to a microscale. Novel manufacturing with photopolymerisable materials can firstly involve use of structured illumination as a novel means to control motorised stages. This technique can be combined with pattern-programmable UV excitation for mask-free photolithographic patterning, continuous photo-curing over larger fields, localised photochemical deposition, or other forms of photo-labile assembly. Process variants can also be envisaged in which arbitrarily positioned fluorescent objects or markers are 'hunted', and then subject to beam excitation for photocuring or targeted photoexcitation. This method could be used, for example, to immobilise individual colloidal quantum dots for use as emitters in quantum technology applications. Multifunctional devices with sensing ability, such as organic lasers for explosives detection, represent another excellent example of automated devices operating under remote conditions. Further examples of the envisaged uses of this technology include: [1] LED microdisplay asset tags for management of high-value objects (artworks, nuclear fuel containers). [2] Passive asset tags containing unique micro-patterns of fluorescent objects (eg. colloidal quantum dots, organic macromolecules) for higher-volume, anti-counterfeiting applications. [3] Customisable continuous-flow micro-reactors for fine chemical manufacturing. [4] Energy harvesting micro-modules to power other autonomous microsystems, where we will focus on organic PV and ambient-radiation (RF) approaches."
Period 01-Jul-2017 - 30-Jun-2021
Quantitative non-destructive nanoscale characterisation of advanced materials
Hourahine, Benjamin (Principal Investigator) Edwards, Paul (Co-investigator) Roper, Richard (Co-investigator) Trager-Cowan, Carol (Co-investigator) Gunasekar, Naresh (Researcher)
"To satisfy the performance requirements for near term developments in electronic and optoelectronic devices will require pioneering materials growth, device fabrication and advances in characterisation techniques. The imminent arrival of devices a few atoms thick that are based on lighter materials such as graphene or boron nitride and also advanced silicon and diamond nano-structures. These devices pose new challenges to the currently available techniques for producing and understanding the resulting devices and how they fail. Optimising the performance of such devices will require a detailed understanding of extended structural defects and their influence on the properties of technologically relevant materials. These defects include threading dislocations and grain boundaries, and are often electrically active and so are strongly detrimental to the efficiency and lifetimes of nano-scale devices (a single badly-behaved defect can cause catastrophic device failure). These defects are especially problematic for devices such as silicon solar cells, advanced ultraviolet light emitting diodes, and advanced silicon carbide and gallium nitride based high power devices (used for efficient switching of large electrical currents or for high power microwave telecoms). For graphene and similar modern 2D materials, grain boundaries have significant impact on their properties as they easily span the whole size of devices. Resolving all of these problems requires new characterisation techniques for imaging of extended defects which are simultaneously rapid to use, are non-destructive and are structurally definitive on the nanoscale. Electron channelling contrast imaging (ECCI) is an effective structural characterisation tool which allows rapid non-destructive visualisation of extended crystal defects in the scanning electron microscope. However ECCI is usually applied as a qualitative method of investigating nano-scale materials, has limitations on the smallest size features that it can resolve, and suffers from difficulties in interpreting the resulting images. This limits this technique's ability to work out the nature of defects in these advanced materials. We will make use of new developments in energy resolving electron detectors, new advances in the modelling of electron beams with solids and the knowledge and experience of our research team and partners, to obtain a 6 fold improvement in the spatial resolution of the ECCI technique. This new energy-filtered way of making ECCI measurements will radically improve the quality of the information that can be obtained with this technique. We will couple our new capabilities to accurately measure and interpret images of defects to other advanced characterisation techniques. This will enable ECCI to be adopted as the technique of choice for non-destructive quantitative structural characterisation of defects in a wide range of important materials and provide a new technique to analyse the role of extended defects in electronic device failure."
Period 01-Jun-2017 - 30-Nov-2020
Doctoral Training Partnership (DTA - University of Strathclyde) | Bryce, Christopher
Martin, Robert (Principal Investigator) Edwards, Paul (Co-investigator)
Period 01-Oct-2014 - 01-Aug-2018
Hysteretic photochromic switching (HPS) of europium-magnesium defects in gallium nitride: a potential route to a new solid-state qubit
O'Donnell, Kevin (Principal Investigator) Edwards, Paul (Co-investigator)
Period 01-Dec-2015 - 30-Mar-2019
Nanoanalysis for Advanced Materials and Healthcare - EPSRC strategic equipment
Martin, Robert (Principal Investigator) Edwards, Paul (Co-investigator) Faulds, Karen (Co-investigator) Florence, Alastair (Co-investigator) Graham, Duncan (Co-investigator) Sefcik, Jan (Co-investigator) Ter Horst, Joop (Co-investigator) Trager-Cowan, Carol (Co-investigator) Uttamchandani, Deepak (Co-investigator) Wark, Alastair (Co-investigator)
Period 08-Nov-2015 - 07-Nov-2019
University Of Strathclyde - Equipment Account
Gachagan, Anthony (Principal Investigator) He, Wenlong (Principal Investigator) Jaroszynski, Dino (Principal Investigator) Martin, Robert (Principal Investigator) McArthur, Stephen (Principal Investigator) McArthur, Stephen (Principal Investigator) Connolly, Patricia (Co-investigator) Edwards, Paul (Co-investigator) Faulds, Karen (Co-investigator) Florence, Alastair (Co-investigator) Graham, Duncan (Co-investigator) Leithead, William (Co-investigator) Sefcik, Jan (Co-investigator) Ter Horst, Joop (Co-investigator) Trager-Cowan, Carol (Co-investigator) Uttamchandani, Deepak (Co-investigator) Wark, Alastair (Co-investigator)
"We propose to undertake an essential and cost effective upgrade of an existing high-power femtosecond laser system at Strathclyde to increase its output power, improve its stability and provide it with the necessary beam control and diagnostics systems to evaluate its performance and control (adjust) several important output beam parameters. The upgrade comprises a cryogenic cooler, to improve the power dissipation and thermal stability of the final laser amplifier Ti:sapphire crystal, a high-energy pump laser for the final amplifier, a wavefront sensor and deformable mirror system, to measure and control the wavefront phase, and an integrated 3rd-order cross-correlator, to measure the laser pulse contrast. The diagnostic systems are necessary to optimise the laser parameters and achieve the desired properties at focus. The cryo-cooler allows cooling of the final amplifier crystal to be increased from 28 W to 80 W, which enables the output power of the laser to be increased to 40 TW using the new high-energy pump laser. The upgraded will improve stability, increase intensity and shorten set-up and alignment times, thus increasing the usable time of the laser system to allow better use of the system and the beamline facilities at Strathclyde. The upgraded laser will be used to deliver the objectives of a Critical Mass proposal (submitted simultaneously) that is part of the ALPHA-X project, which involves 5 universities (Strathclyde, Glasgow, St Andrews, Dundee & Lancaster), and external Collaborators. The research programme includes a study of collective radiation-beam-plasma interactions at high field intensities, the production of ultra-short duration high brightness particle beams from the laser-plasma wakefield accelerator (LWFA), development of new methods of producing coherent and incoherent radiation, and applications of the sources. The applications programme involves an investigation of using high energy electrons for radiotherapy and also methods to produce medical radio-isotopes for medical imaging. The facility will also be used as a platform for engaging with industry through proof-of-concept projects. The upgraded facilities will be transferred to the SUPA Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) when the facility has been constructed."
Period 01-Nov-2014 - 28-Feb-2023

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