Effect of hydrogenation on the electrical and optical properties of p-type Zn 1− xMg xS ySe 1− y epitaxial layers grown on GaAs (100) 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 Zn 0.92Mg 0.08S 0.13Se 0.87 epilayers grown on n-type GaAs (100) substrates by molecular beam epitaxy. The results of the high-resolution transmission electron microscopy showed that the Zn 0.92Mg 0.08S 0.13Se 0.87/GaAs heterostructure had a high-quality heterointerface with sharp interface. After hydrogenation, the acceptor–carrier concentration of the p-type Zn 0.92Mg 0.08S 0.13Se 0.87 decreased due to acceptor neutralization resulting from complexes forming between the hydrogen atoms and the Zn or Se vacancies. After hydrogenation, the PL spectrum showed new donor-bound exciton and free electron-to-acceptor peaks, and the peak position of the donor–acceptor pair peak shifted to higher energy due to hydrogenation neutralization of the acceptor impurities. These results indicate that the crystallinity of the p-type Zn 0.92Mg 0.08S 0.13Se 0.87 epilayers grown on n-type GaAs substrates is improved by hydrogenation and that hydrogenated Zn0 .92Mg 0.08S 0.13Se 0.87 films grown on GaAs substrates hold promise for potential applications as cladding layers in optoelectronic devices operating in the blue–green spectral region.