Transport and generation–recombination mechanisms of nonequilibrium charge carriers in ZnO/In2O3/InSe:Cd heterojunctions

Current–voltage characteristics, spectral characteristics of short-circuit photocurrent and charge generation–recombination kinetics in InSe layer from the contact region of ZnO:Al/In2O3/InSe:Cd heterojunctions are investigated. The structures show photosensitivity in the photon energy range 0.96–3.30 eV. The photosensitivity in the low energy range is determined by absorption threshold of InSe:Cd, while in higher energy range, the optical transparency region of ZnO film prevails. For doping levels of 0.5–1.0 at.%, the ratio of the ambipolar diffusion coefficient and the recombination rate at the InSe surface is decreasing from 1.8 to 0.9 μm.