Tunneling transistors based on MoS2/MoTe2 Van der Waals heterostructures

Two-dimensional transition metal dichalcogenides (TMD's) are promising materials for CMOS application[1], [2] due to their ultra-thin channel with excellent electrostatic control. TMD's are especially well suited for Tunneling Field-Effect Transistors (TFETs) due to their low dielectric constant and their promise of atomically sharp and self-passivated interfaces[3]-[5]. Here we experimentally demonstrate for the first-time band-to-band tunneling (BTBT) in Van der Waals (VdW) heterostructures formed by MoS2 and MoTe2. Density functional theory (DFT) simulations of the band structure show our MoS2-MoTe2 heterojunctions have a staggered band alignment, which boosts BTBT compared to a homojunction configuration. Low-temperature measurements and electrostatic simulations provide understanding towards the role of schottky contacts and the material thickness on device performance. This work provides the prerequisites and challenges required to overcome at the contact region to achieve a steep subthreshold slope and high ON-currents with 2D-based TFETs.

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