NbS2/MoSi2P4 van der Waals Heterojunction: Flexibly tunable electrical contact properties and potential applications for Schottky junction devices

To obtain miniaturized and high-performance nanoelectronic devices, it is still crucially technical problem to realize ohmic contact at metal-semiconductor interface. Here, we construct H-, T-NbS2/MoSi2P4 van der Waals heterojunctions (vdWHs) and theoretically explore their mechanic and electronic behaviors, focusing on electrical contact features and tunability as well as Schottky junction device properties. The suitable Poisson's ratio and sufficient rigidity suggest that such vdWHs are highly favorable to act as electrode or channel materials. The quasi-ohmic contact for H-NbS2/MSP occurs in the intrinsic equilibrium state (ES), and its entire ohmic contact emerges only by a very small interlayer spacing compression. For both H- and T-NbS2/MSP, entire ohmic contacts can be realized by applied appropriate electric field. Based on these studies, we design 5 nm gate-controlled Schottky junction devices. The calculated energy-resolved currents show that the thermal emission transmission plays an important role in rectification, making the rectification ratio exceeding 105, enhanced further by positive gate voltage applied. These behaviors can be identified by the calculated PLDOS, which shows that the highly asymmetric device potential barrier with respect to bias polarity and tuned flexibly by gate voltage results in a highly asymmetric electron transport under different directional biases. Our study provide a new possibility for designing high-performance Schottky junction devices.