Analytical modelling for the dark current of TiO2/ZnS core shell quantum dot (CSQD) photodetectors

Abstract

Dark current has a major contribution in the performance of a Quantum Dot (QD) photodetector. In this paper, a theoretical model is proposed to calculate the dark current of TiO2/ZnS CSQD photodetectors. In this model, the QD sub-band energy levels are calculated using three-dimensional symmetric quantum box considerations. The potential well is considered as finite. The observed theoretical results show the variation of electronic and hole sub-band transition variations with core size. It is also observed that, the dark current is very small, in order of 10−6 and lower for electronic transitions than the hole transitions for smaller, i.e. 8 nm core dimensions.