Localized-State-Dependent Electroluminescence from ZnO/ZnS Core-Shell Nanowires-GaN Heterojunction

ZnO is a very important material for excitonic ultraviolet optoelectronic devices operating above room temperature due to its wide band gap and high exciton binding energy. In this paper, the influences of different degrees of the localized state on the photoluminescence and electro-luminescence properties of the ZnO/ZnS core-shell nanowires-GaN heterojunction are systematically discussed. The physical model for radiative recombination of localized carriers was proposed to explain these phenomena. Our results indicate that surface-coating of ZnS nanoparticles on ZnO nanowires (NWs) is one of the effective ways to manipulate the localized states, and only the appropriate localized state will result in the optimal optoelectronic properties.