Highly conductive GaAsNSe alloys grown on GaAs and their nonalloyed ohmic properties

摘要

Doping properties of Se in GaAsN alloys grown on GaAs (001) substrates by metalorganic-molecular-beam epitaxy were studied. Ditertiarybutylselenide (DtBSe) precursor was used as a Se source. It was found that Se was incorporated into GaAs and GaAsN layers up to a considerable concentration of ~15%. It was also suggested that the N concentrations in GaAsNSe layers were increased by the DtBSe supply. The GaAsNSe layers were heavily doped n type, and the maximum electron concentration was as high as ~1×10(20) cm(–3). With the increase of the carrier concentrations, the resistivity of GaAsNSe dramatically decreased to 1.2×10(–4) Ω cm. This made it possible to have ohmic contacts without thermal annealing, which indicates that GaAsNSe alloys are an attractive candidate for the formation of nonalloyed ohmic contacts.