Title :
Optical characterization of epitaxial GaxIn1-xAs suitable for thermophotovoltaic (TPV) converters
Author :
Wangensteen, T.L. ; Wanlass, M.W. ; Carapella, J.J. ; Moutinho, H.R. ; Mason, Alice R. ; Webb, J.D. ; Abulfotuh, F.A.
Author_Institution :
Nat. Renewable Energy Lab., Golden, CO, USA
fDate :
29 Sep-3 Oct 1997
Abstract :
A preliminary investigation of the optical characteristics of Ga xIn1-xAs epilayers is presented. GaxIn 1-xAs epilayers with x=0.465, 0.400, and 0.277 were prepared by metalorganic vapor-phase epitaxy (MOVPE) to represent a wide spectrum of thermophotovoltaic (TPV) converter applications. Ellipsometric measurements, combined with various characterization techniques and multi-layer modeling, are used to extract n(λ) and k(λ) for these epilayers. The validity of the results was checked by using the experimentally determined optical constants to calculate expected reflectance, and then comparing this result against measured reflectance. Good agreement was obtained in all cases; larger differences were observed for samples having greater surface roughness. Suggestions for improving the optical constant determination procedure are given
Keywords :
III-V semiconductors; gallium arsenide; indium compounds; photovoltaic cells; semiconductor device models; semiconductor device testing; semiconductor epitaxial layers; semiconductor growth; vapour phase epitaxial growth; GaxIn1-xAs thermophotovoltaic cells; GaInAs; ellipsometric measurements; epilayers; metalorganic vapor-phase epitaxy; multi-layer modeling; optical characterization; optical constant determination; reflectance; surface roughness; Epitaxial growth; Epitaxial layers; Indium phosphide; Optical buffering; Optical materials; Optical surface waves; Photonic band gap; Reflectivity; Rough surfaces; Surface roughness;
Conference_Titel :
Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3767-0
DOI :
10.1109/PVSC.1997.654249
