Ultralow Subthreshold Swing 2D/2D Heterostructure Tunneling Field-Effect Transistor with Ion-Gel Gate Dielectrics

Abstract

Two-dimensional (2D) transition-metal dichalcogenide (TMD) semiconductors are promising materials for realizing band-to-band tunneling devices owing to the atomically thin layer and abrupt interface of their heterostructures. In this study, we transferred scalable few-atomic-layer thin films using metal-organic chemical vapor deposition (MOCVD)-grown molybdenum disulfide (MoS2) as an n-channel and CVD-grown molybdenum ditelluride (MoTe2) and tungsten diselenide (WSe2) as p-channels to build van der Waals vertical heterostructures. The heterostructures of intrinsic MoS2 and MoTe2 (or WSe2), each having n-type, ambipolar, or high p-type conductivity, were suitable for tunneling field-effect transistor (TFET) applications. We measured the electrical transport properties of the MoS2/MoTe2 (or WSe2) heterostructures using an ion-gel top gate. The fabricated TFET with MoS2/MoTe2 (or WSe2) heterostructures exhibits a subthreshold swing as low as 9.1 (or 7.5) mV/dec. The negative differential transconductance, negative differential resistance, and temperature-dependent I–V characteristics demonstrate the band-to-band tunneling process. The findings have significant potential for applications in the large-area production of next-generation wearable, stretchable, and flexible low-power electronic devices.