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Dr Keith Heasman


Quality Assurance Manager
Ph-D
+44 (0)1483 682214
17 NC 00
8:30am to 5:30pm

Academic and research departments

Advanced Technology Institute.

Biography

Biography

Keith graduated with a First Class BSc in Physics from the University of Surrey in 1981, and subsequently obtained his PhD in 1985 from the Optoelectronics group in the same department having carried out research on the temperature and pressure dependence of bulk and multi quantum well GaInAsP / InP semiconductor materials, Gunn diodes, LED's and Lasers. Following post graduate studies in the physics department on strained and unstrained quantum well lasers and then as the Philips Fellow in the Electrical Engineering department of the University of Surrey researching Erbium ion implantation into GaAlAs / GaAs quantum well structures Keith left Surrey University and between 1988 and 2004 he was employed as a physicist by BP and subsequently BP Solar, working in silicon solar cell research and development. In 2004 he joined Narec to initially set up the PV Technology Centre and then to enable it to grow and become the world's leading supplier of bespoke silicon concentrator cells. Whilst with BP Solar and Narec, Keith contributed to numerous European and UK funded research projects as well as running, and maintaining several characterisation laboratories dedicated to supporting the companies silicon solar cell manufacturing operations. Keith joined the Surrey Ion Beam Centre as the EPSRC funded Ion Implantation Research Fellow in February 2012.

Research interests

Photovoltaics, Concentrated Photovoltaics, Design, fabrication and characterisation of silicon solar cells, Ion Implantation, Optoelectronics, Semiconductor Lasers, Silicon photonics

Research collaborations

Current and previous collaborators include:Philips Research Laboratories, Fraunhofer Institute for Solar Energy Systems ISE, ENEA Portici, Whitfield Solar, Solar Energy Institute of the Technical University of Madrid, University of Konstanz, Centre for Renewable Energy Systems Technology Loughborough University, Heriot-Watt University, University of Exeter

My publications

Publications

Heasman KC, Mason N, Bruton T, Gledhill S, Hartley O, Morilla C, Roberts S (2004) The Selection and Performance of Monocrystalline Silicon Substrates for Commercially Viable 20% Efficient, LID-free Solar Cells., Proceedings 19th European PV Solar Energy Conference
Heasman KC, Bruton TM, Baistow I, Devenport S, Roberts S, Brown M, Cole A (2011) PROCESS DEVELOPMENT OF LASER GROOVED BURIED CONTACT SOLAR CELLS FOR USE AT CONCENTRATION FACTORS UP TO 100X, Proceedings 22nd European PV Solar Energy
Heasman KC, O'Neill MJ, Russell R, Mason NB, Nagle JP, Bruton TM (1992) Recent Developments in Concentrator Cells & Modules Using Silicon Laser Grooved Buried Grid Cells, Proceedings 11th EC PV Solar Energy Conference pp. 1042-1044
Heasman KC, Bruton TM, Gibbard P, Devenport S, Cole A, Brown LM (2010) LGBC Silicon Solar Cell with modified bus bar suitable for high volume wire bonding, Proceedings of the 6th PVSAT Conference
HEASMAN KC, ADAMS AR, GREENE PD, HENSHALL GD (1987) PRESSURE-DEPENDENCE OF THRESHOLD CURRENT AND CARRIER LIFETIME IN 1.55-MU-M GAINASP LASERS, ELECTRONICS LETTERS 23 (10) pp. 492-493 IEE-INST ELEC ENG
Heasman KC, Bruton TM, Tern R, Sala G, Anton I (2003) Performance prediction of concentrator solar cells and modules from dark I?V characteristics, Progress in Photovoltaics: research and applications 11 pp. 165-178 John Wiley and Sons
The indoor performance of concentrator solar cells and modules at operating conditions is a complex task, owing to the required illumination and temperature conditions, and even more so during extensive procedures, such as on a production line. The solution proposed throughout this paper consists of predicting the illumination I?V characteristic of the solar cells, with the dark I?V curve and the photogenerated current as the only input data. As well as this, the technology-dependent components of the series resistance are obtained from the dark characteristics for quality control. Theory and experiments on several types of concentrator cell have been carried out to validate the method. The equipment to be used on a production line has been developed by IES and used by BP Solar to test up to 25 000 cells and 2000 modules for the 480 kWp power plant using the EUCLIDESTM concentrator. Copyright © 2003 John Wiley & Sons, Ltd.
Baig H, Heasman K, Mallick TK (2013) Experimental investigation of non-uniformity effects in low and medium concentrator silicon solar cells,
Heasman KC, Bruton TM, Roberts S, Heasman KC, Cole A, Tregurtha D, Devenport S (2008) Colour and Shape in Laser Grooved Buried Contact Solar Cells for Applications in the Built Environment, Proceedings 23rd European PV Solar Energy conference pp. 3516-3519
Heasman KC, Gledhill S, Nast O, Russell R, Mason N (2009) High Efficiency Monocrystalline Silicon Solar Cells on B-Doped FZ and Ga- Doped CZ Wafers,
Heasman KC, O'Reilly EP, Witchlow GP, Batty W, Adams AR (1987) Proposal For A Low Threshold Current Long Wavelength Strained Layer Laser, Novel Optoelectronic Devices
Baig H, Heasman KC, Sarmah N, Mallick T (2012) Solar cells design for low and medium concentrating photovoltaic systems, AIP Conference Proceedings 1477 pp. 98-101
The solar cell is the key element of any CPV system, and its design plays an important role in enhancing the performance of the entire system. Special types of cells are required in the CPV systems capable of operating at high concentrations and elevated temperatures. These Concentrator solar cells differ significantly from the usual solar cells in the method of manufacture, the overall cell design and their performance. Systematic design and manufacture of the cell ensures better performance in a given CPV system. A number of factors come into play while designing the solar cell for a specific system these include concentration, cell material properties, expected operating temperature, shape, bus bar configuration and finger spacing. Most of these variables are decided on based on some rules of thumb and PC1D calculations. However, there is scope for design improvement and cell optimization by performing a detailed analysis based on the illumination profile incident on the cell. Recent studies demonstrated the use of Finite element method to analyze the electrical behavior of PV cell under the influence of arbitrarily chosen illumination flux profiles. This study outlines a methodology and analysis procedure while performing a case study of a CPV system under development having a non-uniform illumination profile towards the exit of the concentrator. The LCPV system chosen is the Photovoltaic Facades of Reduced Costs Incorporating Devices with Optically Concentrating Elements (PRIDE) concentrator made of dielectric material. A coupled optical, thermal and electrical analysis is performed on the system to demonstrate the method useful in designing solar cells for low and medium concentrations. © 2012 American Institute of Physics.
HEASMAN KC, HAYES J, ADAMS AR, GREENE PD (1981) TEMPERATURE-DEPENDENCE OF THE TRANSFERRED ELECTRON THRESHOLD CURRENTIN IN1-XGAXASYP1-Y, ELECTRONICS LETTERS 17 (20) pp. 756-757 IEE-INST ELEC ENG
Cole A, Baistow I, Brown L, Devenport S, Drew K, Heasman KC, Morrison D, Bruton TM, Serenelli L, De Iuliis S, Izzi M, Tucci M, Salza E, Pirozzi L (2011) Silicon based photovoltaic cells for concentration-research and development progress in laser grooved buried contact cell technology, AIP Conference Proceedings 1407 pp. 46-49
The Laser grooved buried contact silicon solar cell (LGBC) process employed by Narec currently produces LGBC cells designed to operate at concentrations ranging from 1-100 suns and has demonstrated efficiencies at 50X of over 19% and at 100X of over 18.2% using 300 ¼m CZ silicon[1] wafers. As part of the LAB2LINE[1], APOLLON[2] and ASPIS[3] projects funded under the European Commission Framework Programs (FP6 and FP7) we have made improvements to the LGBC process to improve efficiency or make the cell technology more suitable for industrial CPV receiver manufacturing processes. We describe a process which hybridizes LGBC and more standard screen printing technologies which yields at least a 6% relative improvement at concentration when using more readily available 200 ¼m thick CZ wafers. We describe a pioneering front dicing technique (FDT). The FDT process is important in small cells where edge recombination effects are detrimental to the performance. We show that by using this new technique we can produce cells that perform better at concentration and improve the positioning of the front contact of the cell. We also describe a busbar technology that uses laser processing and electroless chemical plating to allow not only soldering to the front contact of the cell but also wire bonding. The advances in research and development of LGBC cells leading to improved cell performance may provide significant reductions in levilised cost of energy (LCOE) for low to medium CPV systems. © 2011 American Institute of Physics.
Heasman KC, Ramsdale CM, Sherborne J, Bruton TM (2002) Concepts For The Manufacture Of Silicon Solar Cells Modules For Use In Concentrating Systems Up To 5X, Proceedings 29th IEEE PVSEC Conference IEEE
Heasman KC, Cacciato A, Duerinckx F, Baert K, Tonelli E, Ferrazza F, Busto C, Antonelli D, Muller JW, Scherff M, Kontopp MB, Glunz SW, Weber B, Schmiga C, Michl B, Saint-Cast P, Ballif C, De Wolf S, Holman Z, Devenport S, Morrison D, Hahn G, Ebser J, Seren S, Schiele Y, Horbelt R, Terheiden B (2012) The European Project 20plµs: 20 Percent Efficiency on Less Than 100µm Thick Industrially Feasible c-Si Solar Cells., Proceedings 27th European PV Solar Energy Conference
Heasman KC, Bruton T, Brown LM, Cole A, Drew K (2009) Front Dicing Technique for Pre-isolation of Concentrator Silicon Solar Cells,
Heasman KC, Balbuena MA, Russell R, Mason NB, Cunningham DW, Nagle JP, Bruton TM (1997) Large Area High Efficiency Silicon Solar Cells made by the Laser Grooved Buried Grid Process, pp. 761-762
Heasman KC, Cole A, Roberts S, Devenport S, Bruton TM (2008) Laser Grooved Buried Contact Concentrator Solar Cells, Proceedings 4th PVSAT Conference
Colaux JL, Jeynes C, Heasman KC, Gwilliam RM (2015) Certified ion implantation fluence by high accuracy RBS,ANALYST 140 (9) pp. 3251-3261 ROYAL SOC CHEMISTRY
Cole A, Heasman KC, Mellor A, Roberts S, Bruton TM (2006) Laser grooved buried contact solar cells for concentration factors up to 100x,Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, Vols 1 and 2 1 pp. 834-837 IEEE
The Laser Grooved Buried Contact (LGBG) crystalline silicon solar cell is an attractive technology for the production of low-cost concentrator cells. Due to the high-conductivity buried front contact, the metallization pattern may be readily adapted to handle the larger current densities produced at higher concentrations whilst minimizing shading. In the 1990's an efficiency of 18% at 30X concentration without prismatic covers was demonstrated in the EUCLIDES concentrator system [1]. A matrix of cell process conditions has been investigated in order to optimize the emitter and front contact design of the LGBC cell for concentration factors of 50-100X. Efficiencies over 18% at 50X concentration have been measured on 2.56 cm2 cells. Factors limiting the efficiency are discussed and processing improvements are suggested. © 2006 IEEE.
BLOOD P, FLETCHER ED, WOODBRIDGE K, HEASMAN KC, ADAMS AR (1989) INFLUENCE OF THE BARRIERS ON THE TEMPERATURE-DEPENDENCE OF THRESHOLD CURRENT IN GAAS ALGAAS QUANTUM WELL LASERS, IEEE JOURNAL OF QUANTUM ELECTRONICS 25 (6) pp. 1459-1468 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Heasman KC, Bruton TM, Roberts S, Cole A (2007) Laser Grooved Buried Contact Concentrator Cells,
Heasman KC, Mason NB, Roberts S, Bruton TM (2005) Low cost, 100X point focus silicon concentrator cells made by the LGBG, pp. 647-650 IEEE
BRUTON TM, HEASMAN KC (1993) THE ACHIEVEMENT OF 20-PERCENT EFFICIENCY IN A CZ SILICON SOLAR-CELL UNDER CONCENTRATION, CONFERENCE RECORD OF THE TWENTY THIRD IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 1993 pp. 1250-1251 I E E E
Heasman KC, Bruton TM, Roberts S, Mellor A, Cole A (2006) Laser Grooved Buried Contact Solar Cells for Concentration Factors up to 100X,Proceedings 4th WCPEC pp. 834-837
Bruton TM, Roberts S, Heasman KC, Russell R, Warta W, Glunz SW, Dicker J, Knobloch J (2000) Prospects for high efficiency silicon solar cells in thin Czochralski wafers using industrial processes,CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 pp. 180-183 IEEE
Baig H, Sarmah N, Heasman KC, Mallick TK (2013) Numerical modelling and experimental validation of a low concentrating photovoltaic system, Solar Energy Materials and Solar Cells 113 pp. 201-219
Concentrator solar cells need to be designed optimally depending on the concentrating photovoltaic (CPV) system, application and operating conditions to ensure the best system performance. The important factors while designing include concentration ratio, cell material properties, expected operating temperature, cell shape, bus bar configuration, number of fingers their size and spacing. The irradiation incident on the solar cell while being concentrated experiences several losses caused by the different physical phenomena's occurring in the system. A particular issue for CPV technology is the non-uniformity of the incident flux on the solar cell which tends to cause hot spots, current mismatch and reduce the overall efficiency of the system. Understanding of this effect and designing the cell while considering these issues, would help in improving the overall performance of the system. This study focuses on modelling a low concentrating photovoltaic system used for building integration, optimising the cell metallisation and analysing the effects of temperature on the overall output of the system. The optical analysis of the concentrator is carried out using ray tracing and finite element methods to determine electrical and thermal performance under operating conditions. Furthermore, an analysis is made to understand the effects of non-uniformity on the output of the device. About 0.5% absolute drop in solar cell efficiency was observed due to non-uniformity at 5o incident angle. A relative drop of 1.85% was observed in the fill factor due to non-uniformity of the flux distribution. A maximum cell temperature of 349.5 K was observed across the cell in both uniform and non-uniform conditions under an incident solar radiation of 1000 W/m2 which further reduced the performance of the solar cell. The solar cell design was also analysed by varying the number of fingers and the optimum grid design reported. A small prototype concentrator based on the design proposed was made using polyurethane and tested experimentally with the optimized solar cell design. On comparing the results obtained using the experimental data a good agreement in the system output could be seen. The difference in the overall system output was seen to be of the order of 11% which could be due to several losses occurring in the prototype which were not accounted in the model. © 2013 Published by Elsevier B.V. All rights reserved.
Hartley ON, Russell R, Heasman KC, Mason NB, Bruton TM (2002) Investigation of thin aluminium films on the rear of monocrystalline silicon solar cells for back surface field formation,CONFERENCE RECORD OF THE TWENTY-NINTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE 2002 pp. 118-121 IEEE
Heasman KC, Russell R, Bruton TM, Norton B, Eames PC, Zacharopoulos A (2000) A Detailed Optical and Thermal Analysis of a Design for a Low Cost High Efficiency Photovoltaic Concentrator Panel Suitable for Building Integration, Proceedings 16th European PV Solar Energy Conference
Heasman KC, Pirozzi L, Tucci M, Izzi M, Salza E, de Iuliis S, Serenelli L, Bruton TM, Morrison D, Devenport S, Brown LM, Cole A (2009) THE LAB2LINE LASER GROOVED BURIED CONTACT SCREEN PRINTED SOLAR CELLS HYBRID P-TYPE MONOCRYSTALLINE PROCESS, pp. 1318-1322
Devenport S, Roberts S, Heasman KC, Cole A, Tregurtha D, Bruton TM, IEEE (2008) PROCESS OPTIMISATION FOR COLOURED LASER GROOVED BURIED CONTACT SOLAR CELLS,PVSC: 2008 33RD IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE, VOLS 1-4 pp. 414-417
Heasman KC, Bruton TM, Roberts S (2000) The Reduction of Module Power Losses by Optimisation of the Tabbing Ribbon, pp. 2378-2382 James and Jones
Heasman KC, Garrard B, Webster K, Baistow I, Cole A, Brown L, Bruton TM, Roberts S, Devenport S (2009) A SUMMARY OF THE HAVEMOR PROJECT - PROCESS DEVELOPMENT OF SHAPED AND COLOURED SOLAR CELLS FOR BIPV APPLICATIONS, Proc.24th European PV Solar Energy Conference pp. 4276-4279
Heasman KC, Cole A, Roberts S, Bruton TM, Pirozzi L, Serenelli L, Izzi M, Tucci M, Salza E (2008) Studying the Groove Profiles Produced for Fine Line Screen Printed Front Contacts in Laser Grooved Buried Contact Solar Cells., Proceedings 4th PVSAT Conference
Heasman KC, Russell R, Bruton TM, Mason NB (1995) Optimisation of Low-Cost Concentrator Solar Cells, Proceedings 13th European PV Solar Energy Conference pp. 23-27
Heasman KC, Bruton TM, Nagle JP, Cunningham DW, Mason NB, Russell R, Balbuena MA (1994) Recent Progress in the Production of High Efficiency Laser Grooved Buried Grid Silicon Solar Cells,
Heasman KC, Russell R, Burton TM, Norton B, Hyde T, McLarnon D, Zacharopoulos A, Eames PC (2000) The Experimental Fabrication and Characterisation of a Low Cost High Efficiency Photovoltaic Concentrator Panel Suitable for Building Integration, Proceedings 16th European PV Solar Energy Conference
Heasman KC, O'reilly EP, Batty W, Ghiti A (1988) Long wavelength strained layer lasers, IEE Colloquium on `Heterojunction and Quantym Well Devices: Physics, Engineering and Applications pp. 3/1-3/3 IEEE
Heasman KC, Brown LM, Tari O, Roca F, Lancellotti L (2011) Design strategies for solar cells devised to the low wavelength portion of the solar spectrum, Proceedings 26th European PV Solar Energy Conference pp. 1459-1462
Heasman KC, Wilson J, Richards B, Pereau A, Kocher G, Delve J, Devenport S, Cole A, Morrison D (2009) Development of Laser Fired Contact (LFC) Rear Passivated Laser Groove Buried Contact (LGBC) Solar Cells Using Thin Wafers,
Heasman KC, Bruton TM, Morrison D, Devenport S, Brown LM, Cole A Progress of the LAB2LINE Laser Grooved Buried Contact Screen Printed Solar Cells
Hybrid p-type Monocrystalline Process,
03/04/2009
Heasman KC, Bruton T, Cole A, Brown LM, Drew K (2009) FRONT DICING TECHNIQUE FOR PRE-ISOLATION OF CONCENTRATOR SILICON SOLAR CELLS,Proceedings 25th European PV Solar Energy Conference pp. 941-945
Tang YS, Zhang J, Heasman KC, Sealy BJ (1989) Lattice locations of erbium implants in silicon, Solid State Communications 72 (10) pp. 991-993
The lattice locations of erbium implanted in silicon were studied by backscattering angular scanning in combination with photoluminescence measurements. The results show that the positions of erbium implants depend on annealing conditions and have tetrahedral and/or orthorhombic symmetries in different cases. © 1989.
Heasman KC, Cowern EB, Brown L, Cole A, Drew K, Ahn C (2010) INTEGRATED PROCESS AND DEVICE ?TCAD? FOR ENHANCEMENT OF C-SI SOLAR CELL EFFICIENCY,
Heasman KC, Bruton TM, Mason NB, Russell R, Nast-Hartley (2002) Investigation Of Thin Aluminium Films On The Rear Of Monocrystalline Silicon Solar Cells For Back Surface Field Formation,Proceedings 29th IEEE PVSEC Conference pp. 118-121 IEEE
Heasman KC, Bruton TM, Roberts S, Cole A (2007) PC1D modelling of the efficiency of laser grooved buried contact solar cells designed for use at concentration factors up to 100X,
Heasman KC, Scott RDW, Russell R, Bruton TM, Mason NB (1996) The Development of Coloured Silicon Solar Cells for Architectural Applications, Proceedings EuroSun?96
Adams AR, Heasman KC, Hilton J (1987) A reassessment of intervalence band absorption in 1.6¼m (GaIn)(AsP)/InP, Semiconductor Science and Technology 2 (12) pp. 761-764
In the paper the authors re-evaluate the influence of intervalence band absorption on the temperature sensitivity of 1.6 mu m (GaIn)(AsP)/InP lasers and emphasise its general importance in semiconductor lasers operating at several times their threshold current.
Heasman KC, Lesniak M, Neville BM, Hughes AE, Cunningham DW, Mitchell AM, Ford BE, Summers JG, Bruton TM (1991) Factors Influencing the Minority Carrier Diffusion Length in Multicrystalline Silicon Produced in a HEM Furnace, Photovoltaic Specialists Conference, 1991., Conference Record of the Twenty Second IEEE pp. 1010-1014 IEEE
Heasman KC, Bruton TM, Roberts S (2000) The Reduction of Module Power Losses by Optimisation of the Tabbing Ribbon, pp. 2378-2382 James and Jones
Heasman KC, Lesniak MP, Neville BM, Hughes AE (1991) Laser Scanning Analysis of Silicon Solar Cells, Proceedings of the International Conference, held at Lisbon, Portugal, 8?12 April 1991 pp. 644-646 Springer Netherlands
Claudio G, Bass K, Heasman K, Cole A, Roberts S, Watson S, Boreland M (2009) Surface passivation by silicon nitride in Laser Grooved Buried Contact (LGBC) silicon solar cells, SUPERLATTICES AND MICROSTRUCTURES 45 (4-5) pp. 234-239 ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
OREILLY EP, HEASMAN KC, ADAMS AR, WITCHLOW GP (1987) CALCULATIONS OF THE THRESHOLD CURRENT AND TEMPERATURE SENSITIVITY OF A (GAIN)AS STRAINED QUANTUM-WELL LASER OPERATING AT 1.55 MU-M, SUPERLATTICES AND MICROSTRUCTURES 3 (2) pp. 99-102 ACADEMIC PRESS LTD
Heasman KC, Nrton M, Georghiou GE, Guidi V, Vincenzi D, Trovato L, Luisa M, Aleo F, Olson C, Wild-Scholten M, Medina E, Samo A, Cancro C, Graditi G, Roca F, Aitasalo T, Kenny R, Borschchov S, Padovani S, Noack M, Zurro P, Antonini A, Butturi MA, Sturm M, Schineller B, Gogogneau N, Beaudoin G, Jakomin R, Sagnes I, Chernelli C, Martinelli A, Morabito P, Minuto A, Timo G (2011) Optimization of point focus and mirror based spectra splitting CPV systems: Results from the APOLLON project, Proceedings 26th European Photovoltaic Solar Energy Conference and Exhibition pp. 137-144
Heasman KC, Martufi P, Tucci M, Izzi M, Serenelli L, Pirozzi L, Bruton TM, Tregurtha D, Roberts S, Cole A (2008) FINE-LINE SCREEN PRINTING IN LARGE AREA LASER GROOVED, BURIED CONTACT SILICON SOLAR CELLS, Proceedings 23rd European PV Solar Energy conference pp. 1677-1681
Anton I, Sala G, Heasman K, Kern R, Bruton TM (2003) Performance prediction of concentrator solar cells and mdules from dark I-V characteristics, PROGRESS IN PHOTOVOLTAICS 11 (3) pp. 165-178 JOHN WILEY & SONS LTD
Heasman KC, Baistow I, Cole A, Tregurtha D, Brown L, Bruton TM, Roberts S, Devenport S (2009) PROCESS DEVELOPMENT OF SHAPE AND COLOUR IN LGBC SOLAR CELLS FOR BIPV APPLICATIONS,
Heasman KC, Bruton TM, Devenport S, Baistow I, Brown M, Roberts S, Cole A (2011) Development of Laser Grooved Buried Contact Solar Cells for Use at Concentration Factors up to 100X,
Heasman KC, Bruton TM, Roberts S, Mellor A, Cole A (2006) Device Design and Process Optimisation for LGBC Solar Cells for Use Between 50X and 100X Concentration, Proceedings EUROSUN
Heasman KC, Bruton TM, Gibbard P, Devenport S, Cole A, Brown L (2010) LGBC Silicon Solar Cell with modified bus bar suitable for high volume wire bonding,
Heasman KC, Bruton TM, Brown M, Cole A, Roberts S (2007) PROCESS DEVELOPMENT OF COLOURED LGBC SOLAR CELLS FOR BIPV APPLICATIONS, Proceedings 22nd European PV Solar Energy conference
Heasman KC (1998) 480 kWpeak EUCLIDES Concentrator Power Plant Using Parabolic Troughs, Proceedings 2nd World PV Solar Energy Conference pp. 1449-1452
Heasman KC, Russell R, Bruton TM, Norton B, McLarnon D, Zacharopoulos A, Eames PC (1998) Low Cost Facade Integrated Concentrator Photovoltaics, Proceedings 2nd World PV Solar Energy Conference pp. 1449-1452
Heasman KC, Dewallef S, Bruton TM, Morrison DJ, Drew K, Devenport S, Brown LM, Cole A, Pirozzi L, Salza E, Tucci M, Izzi M, Iuliis S, Serenelli L (2010) SCREEN PRINTING IN LASER GROOVED BURIED CONTACT SOLAR CELLS: THE LAB2LINE HYBRID PROCESSES, Proceedings 25th European PV Solar Energy Conference
Heasman KC, Russell R, Mason NB, Cunningham DW, Bruton TM, Roberts S (1995) High Efficiency Production Silicon Solar Cells with Screen Printed Contacts,
Bruton T, Roberts S, Mason N, Heasman K (2005) Low cost, 100X point focus silicon concentrator cells made by the LGBC process, Conference Record of the IEEE Photovoltaic Specialists Conference pp. 647-650
LGBC silicon solar cells have demonstrated efficiencies up to 20% when used in linear focus concentrating systems up to 20X concentration. Small area cells of 1.2 cm2 have been cut from these cells and tested up to 100X concentration for point focus applications. A potential to achieve 20% efficiency at 100X has been recognised and independent results to date have shown an efficiency approaching 18% at 100X. Based on simple variations of a mass production process, analysis indicates that the manufacturing cost for such cells can be below $0.15/Wp. ©2005 IEEE.
Heasman KC, Martinelli G, Medina E, Gigliucci G, Bellia G, Wild-Scholten M, Strum M, Zurro P, Georghiou GE, Sarno A, Kenny R, Borshchov S, Padovani S, Noack M, Gogneau N, Beaudoin G, Jakomin R, Sagnes I, Schineller B, Minuto A, Martinelli A, Timo G (2009) First results on the APOLLON project multi-approach for high efficiency integrated and intelligent concentrating PV modules (systems), pp. 2424-2429 IEEE
Heasman KC, Knobloch J, Dicker J, Glunz SW, Warta W, Russell R, Roberts S, Bruton TM (2000) Prospects For High Efficiency Silicon Solar Cells In Thin Czochralski Wafers Using Industrial Processes,Proceedings 28th IEEE PVSEC Conf pp. 180-183 IEEE
Heasman KC, Russell R, Bruton TM, Mason NB (1996) The Development of Modules Containing High Efficiency Coloured Silicon Solar Cells for use in Building Integration, Proceedings 11th German National Symposium PV Solarenergie pp. 505-509
Heasman KC, Devenport S, Roberts S, Tregurtha D, Cole A, Bruton TM (2008) Process optimisation for coloured laser grooved buried contact solar cells,Proceedings Photovoltaic Specialists Conference IEEE
Heasman KC, Timo G, Noack M, Butturi MA, Sturm M, Wild-Scholten M (2010) ENVIRONMENTAL SUSTAINABILITY OF CONCENTRATOR PV SYSTEMS: PRELIMINARY LCA RESULTS OF THE APOLLON PROJECT, Proceedings 25th European PV Solar Energy Conference
Heasman KC, Cunningham DW, Russell RW, Bruton TM, Roberts S (1998) Interdigitated-Contact Silicon Silicon Solar Cells Made Without Photolithography, pp. 1449-1452
Bruton TM, Sherborne J, Heasman KC, Ramsdale CM (2002) Concepts for the manufacture of silicon solar cell modules for use in concentrating systems up to 5x., CONFERENCE RECORD OF THE TWENTY-NINTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE 2002 pp. 1366-1368 IEEE
HEASMAN KC, BLOOD P, ADAMS AR, FLETCHER ED (1987) PRESSURE-DEPENDENCE OF THE NONRADIATIVE LIFETIME IN GAAS/AIGAAS DOUBLE-HETEROSTRUCTURE LASERS, JOURNAL OF APPLIED PHYSICS 62 (8) pp. 3448-3450 AMER INST PHYSICS
Heasman KC, Webber AW, Tool CJJ, Manshanden P, Tathgar H, Gjerstad O, McCann M, Raabe B, Huster F, Fath P, Ponce-Alcantara S, Coello J, del Canzio C, Roberts S, Bruton TM, Hagel H, Lenkeit B, Schmidt W, Russell R (2006) Record Cell Efficiencies on mc-Si and a roadmap towards 20%, the EC Project TOPSICLE., Proceedings 21st European PV Solar Energy Conference
Heasman KC, Roca F, Serenelli L, Bruton TM, Morrison D, Drew K, Devenport S, Cole A, Brown LM (2011) 20% laser grooved buried contact Cz silicon solar cells for the APOLLON project, Proceedings 26th European PV Solar Energy Conference
Heasman KC, Bruton TM, Cole A, Brown LM, Drew K (2011) Design considerations for silicon solar cells as part of the ASPIS concentrator concept, Proceedings 26th European PV Solar Energy Conference pp. 625-628
Timò G, Martinelli A, Minuto A, Schineller B, Sagnes I, Jakomin R, Beaudoin G, Gogneau N, Noack M, Padovani S, Borshchov S, Kenny R, Sarno A, Georghiou GE, Zurru P, Sturm M, Wild-Scholten M, Bellia G, Gigliucci G, Medina E, Heasman K, Martinelli G (2009) First results on the APOLLON project multi-approach for high efficiency integrated and intelligent concentrating PV modules (systems), Conference Record of the IEEE Photovoltaic Specialists Conference pp. 002424-002429
Next generation concentrating photovoltaic technologies could have a large-scale impact on world electricity production once they will become economically attractive and grid parity will be reached. To proceed towards this important goal, a new large integrated project, APOLLON, has started in July 2008, within the frame of the 7th European Framework program, having the main objective of substantial decrease the Concentrating Photovoltaic (CPV) technology cost to a target value of 2 Euro/W. This ambitious objective is targeted to be reached after five years of research and technological activities in which, both "point focus" and "dense array" CPV technologies will be implemented by facing all the technology-critical issues related to each component of the CPV systems. With this contribution we report the principal results obtained during the first year of the project regarding Multi-Junction (MJ) solar cells, concentrator optics, assembling, tracking and testing. ©2009 IEEE.
Heasman KC, Glatthaar M, Schmiga C, Devenport S, Morrison DJ (2012) Development of Rear Passivated Laser Grooved Buried Contact (LGBC) Laser Fired Contact (LFC) Silicon Solar Cells Using Thin Wafers., Proceedings 27th European PV Solar Energy Conference pp. 1512-1515
Baig H, Heasman KC, Mallick TK (2012) Non-uniform illumination in concentrating solar cells, Renewable and Sustainable Energy Reviews 16 (8) pp. 5890-5909
After a gap of more than two decades, Concentrator Photovoltaics (CPV) technology is once again under spotlight for making use of the best available solar cell technologies and improving the overall performance. CPV finds its use in a number of applications ranging from building integration to huge power generation units. Although the principles of solar concentration are well understood, many practical design, operation, control issues require further understanding and research. A particular issue for CPV technology is the non-uniformity of the incident flux which tends to cause hot spots, current mismatch and reduce the overall efficiency of the system. Understanding of this effect requires further research, and shall help to employ the most successful means of using solar concentrators. This study reviews the causes and effects of the non-uniformity in the CPV systems. It highlights the importance of this issue in solar cell design and reviews the methods for the solar cell characterization under non-uniform flux conditions. Finally, it puts forward a few methods of improving the CPV performance by reducing the non-uniformity effect on the concentrator solar cells. © 2012 Elsevier Ltd.
HEASMAN KC, ADAMS AR, PLUMB RG (1987) SCANNING THE LASER GAIN SPECTRUM USING DISTRIBUTED FEEDBACK AND HYDROSTATIC-PRESSURE, ELECTRONICS LETTERS 23 (11) pp. 555-557 IEE-INST ELEC ENG
Heasman KC, Bruton T, Brown L, Cole A, Drew K (2009) Front Dicing Technique for Pre-isolation of Concentrator Silicon Solar Cells,
TANG YS, HEASMAN KC, GILLIN WP, SEALY BJ (1989) CHARACTERISTICS OF RARE-EARTH ELEMENT ERBIUM IMPLANTED IN SILICON, APPLIED PHYSICS LETTERS 55 (5) pp. 432-433 AMER INST PHYSICS
Heasman KC, O'Reilly EP, Adams AR (1989) Characterization and Design of Semiconductor Lasers Using Strain, NATO ASI Series 189 pp. 279-301 Springer New York
Heasman KC, Russell R, Nagle JP, Bruton TM (1993) The Achievement of 20% Efficiency in a CZ Silicon Solar Cell Under Concentration, Proceedings 23rd IEEE PV Spec. Conference pp. 1250-1251 IEEE
Barbé Jérémy, Lee Harrison K. H., Toyota Hiroyuki, Hirose Kazuyuki, Sato Shin-ichiro, Ohshima Takeshi, Heasman Keith, Tsoi Wing C. (2018) Characterization of stability of benchmark organic photovoltaic films after proton and electron bombardments,Applied Physics Letters 113 (18) 183301 AIP Publishing
Organic solar cells have attractive potential for space applications as they have very high specific power (power generated per weight) and ultra-high flexibility (to reduce stowed volume). However, one critical issue is whether they are stable under the harsh space environment, particularly their stability under high energy, high flux, electron and proton bombardment. In this paper, the stability of benchmark organic photovoltaic layers under proton bombardment (150 keV with a fluence of 1 × 1012/cm2) and electron bombardment (1 MeV with a fluence of 1 × 1013/cm2) under vacuum is investigated. Raman spectroscopy, photoluminescence spectroscopy, and optical reflectance spectroscopy are applied to study their chemical/structural, photo-chemical/morphological, and optical stability after the bombardments. The results show that all the benchmark organic photovoltaic films are stable under the radiation, implying that organic solar cells could be feasible for space applications.
Barbé Jérémy, Hughes Declan, Wei Zhengfei, Pockett Adam, Lee Harrison K. H., Heasman Keith C., Carnie Matthew J., Watson Trystan M., Tsoi Wing C. (2019) Radiation Hardness of Perovskite Solar Cells Based on Aluminum-Doped Zinc Oxide Electrode Under Proton Irradiation,Solar RRL 3 (12) 1900219 Wiley
Perovskite solar cells (PSCs) have gained increasing interest for space applications. However, before they can be deployed into space, their resistance to ionizing radiations, such as high?energy protons, must be demonstrated. Herein, the effect of 150 keV protons on the performance of PSCs based on aluminum?doped zinc oxide (AZO) transparent conducting oxide (TCO) is investigated. A record power conversion efficiency of 15% and 13.6% is obtained for cells based on AZO under AM1.5G and AM0 illumination, respectively. It is demonstrated that PSCs can withstand proton irradiation up to 10¹³ protons cm{² without significant loss in efficiency. From 10¹t protons cm{², a decrease in short?circuit current of PSCs is observed, which is consistent with interfacial degradation due to deterioration of the Spiro?OMeTAD holes transport layer during proton irradiation. The structural and optical properties of perovskite remain intact up to high fluence levels. Although shallow trap states are induced by proton irradiation in perovskite bulk at low fluence levels, charges are released efficiently and are not detrimental to the cell's performance. This work highlights the potential of PSCs based on AZO TCO to be used for space applications and gives a deeper understanding of interfacial degradation due to proton irradiation.