Title :
ZnSe window layers for GaAs solar cells
Author :
Yater, J.A. ; Landis, G.A. ; Bailey, S.G. ; Olsen, L.C. ; Addis, F.W.
Author_Institution :
NASA Lewis Res. Center, Cleveland, OH, USA
Abstract :
We examine ZnSe as a potential window-layer material for GaAs. ZnSe is nearly lattice-matched to GaAs, as well as to GaInP, and has a bandgap of 2.67 eV, which is significantly higher than that of AlGaAs. If good surface passivation of the GaAs by ZnSe can be achieved, a significant improvement in short-circuit current (and hence efficiency) should be possible. We have characterized n-type ZnSe deposited by OMCVD on GaAs for a variety of growth conditions and doping levels. An 80-nm thick n-ZnSe film deposited on epitaxial n-GaAs leads to a fivefold increase in photoluminescence (PL) intensity compared to a bare sample, indicating reduced surface recombination (SRV). The wavelength dependence of the backside PL signal is approximately constant for the ZnSe-coated sample, while it increases with wavelength for the bare wafer. This also indicates a significant reduction in SRV
Keywords :
CVD coatings; II-VI semiconductors; III-V semiconductors; energy gap; gallium arsenide; passivation; photoluminescence; semiconductor growth; semiconductor materials; semiconductor thin films; solar cells; surface recombination; zinc compounds; 2.67 eV; 80 nm; GaAs; GaAs solar cells; GaAs-ZnSe; OMCVD; ZnSe window layers; backside photoluminescence signal; bandgap; doping levels; efficiency improvement; epitaxial n-GaAs; growth conditions; lattice-match; photoluminescence intensity increase; reduced surface recombination; short-circuit current improvement; surface passivation; wavelength dependence; Absorption; Aluminum; Coatings; Gallium arsenide; Humidity; Lattices; Passivation; Photonic band gap; Photovoltaic cells; Zinc compounds;
Conference_Titel :
Photovoltaic Specialists Conference, 1996., Conference Record of the Twenty Fifth IEEE
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-3166-4
DOI :
10.1109/PVSC.1996.563947
