Realization of High Current Gain for Van der Waals MoS 2 /WSe 2 /MoS 2 Bipolar Junction Transistor.

Two-dimensional (2D) materials have attracted great attention in the past few years and offer new opportunities for the development of high-performance and multifunctional bipolar junction transistors (BJTs). Here, a van der Waals BJT based on vertically stacked n + -MoS 2 /WSe 2 /MoS 2 was demonstrated. The electrical performance of the device was investigated under common-base and common-emitter configurations, which show relatively large current gains of α ≈ 0.98 and β ≈ 225. In addition, the breakdown characteristics of the vertically stacked n + -MoS 2 /WSe 2 /MoS 2 BJT were investigated. An open-emitter base-collector breakdown voltage (BV CBO ) of 52.9 V and an open-base collector-emitter breakdown voltage (BV CEO ) of 40.3 V were observed under a room-temperature condition. With the increase in the operating temperature, both BV CBO and BV CEO increased. This study demonstrates a promising way to obtain 2D-material-based BJT with high current gains and provides a deep insight into the breakdown characteristics of the device, which may promote the applications of van der Waals BJTs in the fields of integrated circuits.