Polycrystalline Indium Phosphide Solar Cells Fabricated on Molybdenum Substrates

Abstract

Heterojunctions on polycrystalline indium phosphide films are fatbricated and characterized. The InP films are chemically deposited on molybdenum substrates. Cuprous selenide films, being cubic in crystal structure and degenerate in conduction, are prepared on n-type InP films. CuxSe/InP thin film solar cells have efficiencies of up to 1.7% with a short circuit current density of 11 mA/cm2 under AM 1 simulated irradiation. Furthermore, CdS/InP heterojunction solar cells are fabricated by evaporating indium-doped CdS films on zinc-doped InP surfaces. The efficiency directly increases with the annealing temperature of the cells up to 2.0% with a short-circuit current density of 18 mA/cm2. A collection efficiency of 70% is obtained at a wavelength of 0.65 µm from a spectral response curve. In addition, the electron diffusion length is calculated to be 0.2 µm, which determines the lower collection efficiency at longer wavelengths.