Van der Waals Bipolar Junction Transistor Using Vertically Stacked Two-Dimensional Atomic Crystals

The majority of microelectronic devices rely on a p-n junction. The process of making such a junction is complicated, and it is difficult to make layers that form a junction with an atomic thickness. In this study, bipolar junctions are made by using 2D atomic crystalline layers and even a single layer in which 2D layers adhere together to form a heterostructure via van der Waals forces. A vertical 2D bipolar junction transistor (V2D-BJT) is studied for the first time. It uses an MoS2/WSe2/MoS2 heterostructure and has an n-p-n configuration that exhibits a maximum common-base current gain of approximate to 0.97 and a stable common-emitter current gain (beta) of 12 with a nanowatt power consumption. In the first attempt at gas sensing, it shows outstanding performance, exhibiting a very fast response and recovery time (9 and 35 s, respectively) with a power dissipation of only 2 nW. This study demonstrates the potential application of the V2D-BJT in nanowatt power amplifiers as well as fast-response and low-power gas sensors.