Prof Peter Blood
Overview
Email:BloodPTelephone:
Location:N/1.08
Research Interests
Since about 1983 my research has been conncerned with the physics of quantum confined semiconductor structures, in particular with regard to their use in laser diodes and light emitting diodes. At Philips interest was in GaAs/AlGaAs lasers for CD applications, then at Cardiff work moved on to red-emitting lasers in the GaInP system in collaboration with Epitaxial Products International, now IQE, located on the outskirts of the city at St Mellons. More recent projects have included work on blue-emitting GaN structures in collaboration with Sheffield and Cambridge and current interest is focused on quantum dots.
In the course of this research there have been two significant contributions to techniques for the study of laser structures. The first was observation of the true spontaneous emission spectrum from laser diodes under operating conditions. This enabled us to resolve early controversy regaring the lasing mechanism in quantum wells and later to identify carrier leakage paths in GaInP lasers. We also established the correct approach to interpretation of measurements of differential quantum efficiency.
More recently we have developed the segmented contact method for measurement of optical gain, extending it to measure the spontaneous emission spectrum in real units (we believe this is the only method so far developed to do this). We have measured the TE and TM polarised gain in strained quantum wells for the first time. We have extended the method to measure the population inversion factor to investigate non-thermal carrier distributions in quantum dots. Recent work is focused on the consequences of carrier localisation in dots, which we have shown to modify the recombination characteristics significantly from those predicted by "global" theories used in many present-day calculations of quantum dot laser characteristics.
Measures of Esteem
I am a member of the Lasers and Electro-Optics Society (LEOS) which is affiliated to the Institution of Electrical and Electronic Engineers (IEEE) to which I have been elected a Fellow. I am also a member of the Optical Society of America and a Fellow of the Institute of Physics.
I have served as programme committee member for the Conference on Lasers and Electro-Optics (CLEO) and am chair of the European Area Programme Committee for the bi-annual International Conference on Semiconductor Lasers (ISLC) to be held in Sorrento in September 2008.
I have given Short Courses and invited Tutorials on various aspects of the physics of quantum-confined lasers diodes at a number of international conferences, eg: Photonics West (San Jose), CLEO (Long Beach), ISLC (Matsue, Japan), and have contributed lectures to a Summer School on diode lasers held in Cork (twice) Wales (which I also organised) and Beijing. I will present an invited short course on quantum dot lasers at CLEO in May 2008. I am an Associate Editor of Journal of Quantum Electronics.
I am Chair of the Steering Committee of the EPSRC National Centre for III-V Technologies at Sheffield (from 1999) and was a member of the EPSRC Strategic Advisory Team for Materials (2002-2006). I have also served on Research Proposal Review Panels for DFG (Germany).
Teaching
I chaired the group which set up the new MSc in Biophotonics, which is operated jointly with the School of Bioscience, winning £174k funding from EPSRC. I currently teach one module on the course on Nanostructures and Optical Manipulation, and organise the Project Module. I teach a fourth year undergraduate course on nanostructure optoelectronics and give an informal Post graduate course on quantum confined structures and laser diode physics which runs over a two-year cycle.
Admin Duties
I have some university responsibilities, and consequently a reduced teaching and admin load in Physics.
Publications
Refereed Journals
Localised Auger recombination in quantum dot lasers, Peter Blood, Helen Pask, Huw D Summers and Ian Sandall, Journ Quantum Electron 43 (12) pp1140-1146 (2007)
Time Evolution of the Screening of Piezoelectric Fields in InGaN Quantum wells. Iain H. Brown, Peter Blood, Peter M. Smowton, John D. Thomson, Santiago M. Olaizola, A. Mark Fox, Peter J. Parbrook, and Weng W. Chow. Journ Quantum Electron 42 (12) pp. 1202-1208 (2006)
Light-Current characteristics of quantum dots with localised recombination, H J Pask, H D Summers and P Blood. Appl Phys Letts 87 083109 (2005)
Dynamics of the wetting layer-quantum dot interaction in InGaAs self-assembled systems D W Matthews, H D Summers, P M Smowton, P Blood, P Rees, and M Hopkinson, IEEE Journ Quantum Electron 41, (2005) 344-350
Optical absorption cross section of quantum dots, S W Osborne, P Blood, P M Smowton, Y C Xin, A Stintz, D Huffaker and L F Lester, J Phys Condens Matter 16 (2004), S3749-S3756
State filling in InAs quantum-dot laser structures, S W Osborne, P Blood, P M Smowton, J Lutti, Y C Xin, A Stintz, D Huffaker and L F Lester, IEEE Journ Quantum Electron 40, 1639, (2004)
Characterisation of semiconductor laser gain media by the segmented contact method, P Blood, G M Lewis, P M Smowton, H D Summers, J Thomson and J Lutti, IEEE Journ Selected Topics in Quantum Electronics 9, 1275 (2003)
Measurement of transverse electric and transverse magnetic spontaneous emission and gain in tensile strained GaInP laser diodes. G M Lewis, P. M. Smowton, P. Blood, G. Jones, and S. Bland. Appl. Phys. Lett. 80, 3488 (2002)
Measurement of true spontaneous emission spectra from the facet of diode laser structures G. M. Lewis, P. M. Smowton, J. D. Thomson, H. D. Summers, and P. Blood. Appl. Phys. Lett. 80, 1 (2002)
Thermodynamic balance in quantum dot lasers. H D Summers, J D Thomson, P M Smowton, P Blood and M Hopkinson. Semic Sci and Technol 16 (2001) 1-4
Minority Carrier Effects in GaInP Laser Diodes. S.A. Wood, C.H. Molloy, P.M. Smowton, P. Blood, and C.C. Button, Journ Quantum Electron, 36, (2000) 742- 750
On the dimensionality of optical absorption, gain and recombination in quantum-confined structures. P Blood, Journ Quantum Electron 36 (2000) 354-362
Determination of single-pass optical gain and internal loss using a multi-section device. J D Thomson, H D Summers, P J Hulyer, P M Smowton and P Blood. Appl Phys Letts 75 (1999) 2527-2529
Electron transport in AlGaInP quantum well lasers. S A Wood, C H Malloy, P M Smowton, P Blood, D J Somerford and C C Button. Appl Phys Letts 75 (1999) 1748-1750
Measurement of Optical Mode Loss in visible emitting lasers, P C Mogensen, P M Smowton and P Blood, Appl Phys Letts, 71 (14) (1997) 1975-1977
The differential efficiency of quantum well lasers, P M Smowton and P Blood, Journ Quantum Electron, Selected Topics in Quantum Electronics, 3 (2) (1997) 491-498
Books and Chapters
The Electrical Characterisation of Semiconductors: Measurement of Minority Carrier Properties, J W Orton and P Blood, Academic Press (1990) (251pp). Majority Carriers and Electron States. P Blood and J W, Orton, Academic Press (1992) (735pp)
Heterostructures in Lasers, P Blood, in "Physics and Technology of Heterojunction Devices", ed D V Morgan and R H Williams, Peter Peregrinus Ltd (1991).
Visible-emitting AlGaInP laser diodes, P M Smowton and P Blood. in” Strained layer quantum wells and their applications”, ed M O Manasreh, Gordon and Breach, 1997. Chapt 9, pp431-487
Fundamentals of Quantum Wells: GaAs-based structures. P Blood, in “Encyclopaedia of Modern Optics”, editor in chief: Bob D Guenther, Elsevier 2004.
Visible laser diodes: properties of III-V red-emitting laser diodes, P Blood. in “Handbook of laser technology and applications” IoP Publishing, editor in chief: Colin Webb. IoP Publishing 2004
Biography
I obtained a BSc and PhD in physics from the University of Leeds. I was first employed at Philips Research Laboratories in Redhill and spent a year seconded to AERA at Harwell working on ion implanatation doping of Si. This led to a period as a resident visitor at Bell Labs at Murray Hill, New Jersey, working on Rutherford Scattering and solid phase epitaxial regrowth in Si. On returning to Philips I worked on GaAs heterostructures growth by moleclar beam epitaxy which led to a research programme on quantum well lasers. I moved to Cardiff in 1990 to establish a research activity on the physics of optoelectronic devices.
Postgraduate Students
With colleagues, I co-supervise three PhD students working on self-assembled and colloidal quantum dots.