Effects of interface state density on the carrier transport and performance of metal-insulator-semiconductor (MIS) type thin film solar cells

Interface state density plays a significant role in determining the behaviour and characteristics of optoelectronic devices. In this paper, we investigated the effect of the interface state density on the carrier transport and performance in ZnO based-metal-instulator-semiconductor (MIS) type solar cells. Semi-analytical calculations were performed to obtain the solar cell's performance characteristics, i.e., the short circuit current, open-circuit voltage, fill-factor, and efficiency. Most possible carrier transport mechanisms including minority carrier diffusion, field emission (tunnelling) and carrier recombination were taken into account in investigating the role interface state density on the current profile. It was found that the effect of interface state density is dependent on the oxide thickness. At thicknesses higher than the critical thickness of the oxide layer the increase of the density of states causes the performance of the solar cells to drop.