We report the use of a simple close-spaced vapor transport technique for the growth of high-quality epitaxial GaAs films using potentially inexpensive GaAs powders as precursors.
n-GaAs films were grown epitaxially on n(+)-GaAs substrates by a close-spaced vapor transport method and their photoelectrochemical energy conversion properties studied. Under 100 mW cm(-2) of ELH solar simulation, conversion efficiencies up to 9.3% for CSVT n-GaAs photoanodes were measured in an unoptimized ferrocene/ferrocenium test cell. This value was significantly higher than the 5.7% measured for similarly doped commercial n-GaAs wafers. Spectral response experiments showed that the higher performance of CSVT n-GaAs films relative to the commercial wafers was due to longer minority carrier diffusion lengths (L(D)), up to 1,020 nm in the CSVT films compared to 260 nm in the commercial n-GaAs wafers. Routes to improve the performance of CSVT GaAs and the implications of these results for the development of scalable GaAs-based solar energy conversion devices are discussed.
The materials Cu 3 PQ 4 (Q ¼ S, Se) of the enargite structure are studied as photovoltaic (PV) absorbers.Optical band gaps in the series Cu 3 PS 4Àx Se x (0 # x # 4) are found to range from 2.36 eV (x ¼ 0) to 1.35 eV (x ¼ 4). Seebeck measurements on powder samples at room temperature yield large positive values (>100 mV K À1 ) indicating p-type behavior. Hole carrier concentrations are found in the range of 10 16 -10 17 cm À3 . Crystal structures of Cu 3 PS 1.89 Se 2.11 and Cu 3 PS 0.71 Se 3.29 are refined in the orthorhombic space group Pmn2 1 with the unit-cell parameters -Cu 3
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.