HETEROEPITAXY AND CHARACTERIZATION OF CUINSE2 ON GAAS(001)

CuInSe2 (CIS) films with Cu/In ratios of gamma = 0.81-1.81 have been g rown on (001)-oriented GaAs substrates by molecular beam epitaxy at su bstrate temperatures of T-s = 350-550 degrees C. Film properties were found to be substantially different for Cu- and In-rich regions. Cu-ri ch films were p-type, and streaky reflection high-energy electron diff raction (RHEED) patterns and sharp photoluminescence (PL) emissions we re observed, suggesting high quality epitaxial films. In-rich films we re highly resistive, and contained a large number of twins formed on { 112} planes. A broad and strong PL emission, a donor-acceptor pair emi ssion, was observed, which blue-shifted with increasing excitation pow er, indicating heavy compensation.