Dr. Andrew Norman was awarded his bachelor's degree in materials science from Imperial College of Science and Technology, University of London. He then pursued his doctorate at the University of Oxford under the supervision of Dr. G. R. Booker doing studies on transmission electron microscopy (TEM) of Group III-V semiconductor alloys, during which pioneering discoveries were made on phase separation and atomic ordering in these alloys. He spent a year at Plessey Research (Caswell) Ltd. performing epitaxial growth of III-V semiconductors and devices by LPE and MOCVD and then returned to the University of Oxford as a postdoctoral researcher to work on a Joint Optoelectronic Research Project performing TEM of MOCVD grown InP-based materials and a LINK project involving TEM studies of non-planar and localized epitaxy of MOCVD III-V semiconductor materials. He was then awarded an EPSRC Visiting Fellowship at the Interdisciplinary Research Centre for Semiconductor Materials, Imperial College, for the study of atomic ordering and phase separation phenomena during MBE of III-V alloys. Following this, he remained at Imperial College running an III-V MBE system specializing in the growth of narrow bandgap III-V semiconductor materials for basic physics and materials studies and novel devices. He then returned briefly to the Department of Materials in Oxford to study narrow band gap III-V semiconductors and quantum dots grown by MOCVD at the Clarendon Laboratory.

In 1997, Norman joined NREL as a senior research associate to study lateral modulations in III-V semiconductor short-period strained layer superlattices and atomic ordering in III-V alloys, and established collaborations with the NREL's III-V team to study materials issues in III-V and other novel semiconductor alloys of interest for multi-junction solar cells. He became a permanent employee at NREL in 2000. Since then he has pursued research into a wide range of topics, including quantum dot solar cells, III-V metamorphic multi-junction solar cells, molecular-based upconversion, novel epitaxial relationships, and more recently, epitaxial growth of CZTS, and the fabrication of high efficiency single crystal Si and Si-based tandem cells.

Research Interests

Norman's research interests include epitaxial growth including novel epitaxial relationships, atomic ordering, phase separation, and defect formation etc.; transmission and scanning transmission electron microscopy of materials; epitaxially grown quantum dots and wires; next generation photovoltaic devices; multi-junction solar cells; solid-state lighting; low-cost, large-area fabrication routes for semiconductor devices.

Education

B.S. Materials Science, Imperial College of Science and Technology, University of London

Ph.D., University of Oxford

Featured Work

"PbTe colloidal nanocrystals: synthesis, characterization, and multiple exciton generation" J. E. Murphy, M. C. Beard, A. G. Norman, S. P. Ahrenkiel, J. C . Johnson, P. Yu, O. I. Micic, R. J. Ellingson, and A. J. Nozik, J. Am. Chem Soc. 128 (2006) 3247.

"Nanocrystalline TiO₂ solar cells sensitized with InAs quantum dots" P. Yu, K. Zhu, A. G. Norman, S. Ferrere, A. J. Frank, and A. J. Nozik, J. Phys. Chem. B. 110 (2006) 25451.

"40.8% efficient inverted triple-junction solar cell with two independently metamorphic junctions" J. F. Geisz, D. J. Friedman, J. S. Ward, A. Duda, W. J. Olavarria, T. E. Moriarty, J. T. Kiehl, M. J. Romero, A. G. Norman, and K. M. Jones, Appl. Phys. Lett. 93 (2008) 123505.

"Theoretical and experimental examination of the intermediate-band concept for strain-balanced (In,Ga)As/Ga(As,P) quantum dot solar cells" V. Popescu, G. Bester, M. C. Hanna, A. G. Norman, and A. Zunger, Phys. Rev. B 78 (2008) 205231.

"TEM and TED observations of alloy clustering in LPE (001) GaInAsP layers" A. G. Norman and G. R. Booker, J. Appl. Phys. 57 (1985) 4715.

"Mechanism for CuPt-type ordering in mixed III-V epitaxial layers" B. A. Philips, A. G. Norman, T.-Y. Seong, S. Mahajan, G. R. Booker, M. Skowronski, J. P. Harbison and V. G. Keramidas, J. Crystal Growth 140 (1994) 249.

"Observation of {111} ordering and [110] modulation in MBE GaAs_1-ySb_y layers: possible relationship to surface reconstruction during layer growth" I. J. Murgatroyd, A. G. Norman and G. R. Booker J. Appl. Phys. 67 (1990) 2310.

"TED, TEM and HREM studies of atomic ordering in Al_xIn_1-xAs epitaxial layers grown by OMVPE" A. G. Norman, R. E. Mallard, I. J. Murgatroyd, G. R. Booker, A. H. Moore and M. D. Scott, Proc. of Microsc. of Semicond. Mater. Conf., Oxford UK April 1987, Inst. Phys. Conf. Ser. No. 87 (1987) p77.

"BGaInAs alloys lattice-matched to GaAs" J. F. Geisz, D. J. Friedman, J. M. Olson, S. M. Kurtz, R. C. Reedy, A. B. Swartzlander, B. M. Keyes, and A. G. Norman, Appl. Phys. Lett. 76 (2000) 1443.

"Electronic structure of self-organized InAs/GaAs quantum dots bounded by {136} facets" W. Yang, H. Lee, T. J. Johnson, P. C. Sercel, and A. G. Norman, Phys. Rev. B 61 (2000) 2784.