Tunneling transport in WSe2-MoS2 heterojunction transistor enabled by a two-dimensional device architecture

Heterojunctions made of two-dimensional (2D) semiconducting materials provide promising properties for the realization of tunnel field effect transistors (TFETs). The absence of dangling bonds allows the formation of sharp hetero-interfaces, which enables the reduction of parasitic components arising due to interface traps [1]. In this work, we demonstrate band-to-band tunneling (BTBT) between layers of WSe2 and MoS2 that are contacted with few-layered graphene (FLG) on both sides of the junction and completely encapsulated with hexagonal boron nitride (h-BN). Additionally, we also use the FLG as a gate electrode, which allows us to realize devices made entirely of different 2D materials. Previous reports on WSe2-MoS2 junctions showing tunneling transport use a combination of high-k dielectrics [2]–[5], ion gel dielectric[6], doped flakes[5], or different sets of contact metals[3], [4]. We observe negative differential resistance (NDR) confirming the tunneling transport in our devices without using any of the above mentioned additional fabrication steps, showing the potential in terms of further optimization.