Performance Analysis of p-LPZO/n-GZO and p-SZO/n-GZO Homojunction UV Photodetectors

Abstract

A comprehensive analytical model for the dark current and photoresponsivity of ZnO thin film based homojunction ultraviolet (UV) photodetector (PD) is proposed in this study. The detailed insight about the effects of different acceptor doping materials in the illuminated surface layer is presented in this work. The recombination velocity of the carriers and the effect of applied reverse bias, specifically on the responsivity of p-n homojunction based UV PD are elucidated. The impact of two different types of dual ion beam sputtering (DIBS)-grown acceptor-doped ZnO (Sb:ZnO and Li–P:ZnO) materials on the responsivity is also discussed. The investigation results reveal that an increase in applied reverse bias results in higher responsivity due to depletion region increase leading to higher charge carrier photogeneration. Further, on comparing the results with the experimentally reported ZnO-based homojunction UV PDs, it is found that, by incorporating Sb:ZnO as p-type layer, dark current and responsivity values are improved by ~38 and ~63.7%, respectively. Hence, the developed model is significant for the design optimization of high-performance ZnO thin film-based UV homojunction PDs. © 2020 Elsevier Ltd