Hydrogenation effects on the electrical and optical properties of p-type ZnS ySe 1− y epilayers grown on GaAs (1 0 0) substrates

Abstract

Capacitance-voltage (C-V) and photoluminescence (PL) measurements have been carried out to investigate the hydrogenation effects on the electrical and the optical properties in p-type ZnS 0.06Se 0.94 epilayers grown on n-type GaAs (1 0 0) substrates by molecular beam epitaxy. The results of the transmission electron microscopy measurements showed that the ZnS 0.06Se 0.94/GaAs heterostructures had high-quality heterointerfaces. After hydrogenation, the acceptor concentration of the p-ZnS 0.06Se 0.94 decreased due to acceptor neutralization resulting from complexes forming between the hydrogen atoms and the Zn or Se vacancies. The PL spectra for the hydrogenated p-ZnS 0.06Se 0.94 showed that the peak positions of the donor–acceptor pair peak and its phonon replicas shifted to the higher energy side and that the donor-bound exciton peak appeared. These results indicate that the crystallinity of the p-type ZnS y Se 1− y epilayers grown on n-type GaAs substrates is improved by hydrogenation and that the hydrogenated ZnS y Se 1− y films grown on GaAs substrates hole promise for potential applications as waveguide layers for optoelectronic devices operating in the blue-green spectral region.