Optical and electrical characteristics of ZnO/Si heterojunction

Self-assembled ZnO nanorods have been synthesized on a seeded Si substrate by a simple chemical bath deposition method at a temperature of 80°C. Room-temperature photoluminescence analysis revealed material of high optical quality with a low density of defects that can be reduced by post growth annealing. Current–voltage measurements on these devices showed excellent rectification. Junction characteristics were also studied using capacitance–voltage measurements and showed that the junction characteristics are mainly determined by the properties of the p-Si substrate. Based on the energy band diagram and possible interface states at the junction, it was suggested that the current transport in the device is predominantly determined by hopping of charge carriers between localized states through a multi-step tunneling process.