Tunable reverse rectification of layed Janus MSeS (M = Hf, Zr) and SnS2 heterojunctions

Abstract

Two-dimensional (2D) Janus transition metal dichalcogenides (JTMDs) exhibit suitable band gaps and strong visible light absorption, which are extensively applied to the field of optoelectronic devices. Here, we investigate the electronic properties of 2D JTMDs MSeS (M = Hf, Zr) and SnS2 van der Waals heterojunction through density functional theory. The calculated electronic properties reveal that ZrSeS/SnS2 heterojunction has a type-I band alignment, while HfSeS/SnS2 heterojunction has a type-II band alignment. We build the diodes based on the MSeS (M = Hf, Zr)/SnS2 heterojunctions and study the electronic transport. The currents of the devices exhibit asymmetry, and the negative turn-on voltages suggest that constructed devices are backward diodes. Moreover, it is found that the gate voltage can modulate the rectifying ratio, and the rectifying performance of ZrSeS/SnS2 is better than that of HfSeS/SnS2..