Dopant-mediated carrier tunneling in short-channel two-dimensional transistors†

Substitutional doping has played a pivotal role in silicon-based electronics and holds equivalent importance for emerging two-dimensional (2D) semiconductors, which show promise for advanced node technologies. However, the intricate role of dopant atoms in 2D transistors, particularly in short-channel cases, remains elusive and poses a challenging task for experimental exploration. In this study, using density functional theory (DFT) calculations and quantum transport simulations, we reveal the dual functionalities of V dopants in short-channel 2D transistors constructed with lateral VS₂–MoS₂–VS₂ heterostructures. Depending on the channel length, the V dopant in the MoS₂ channel, manifested by localized density of states (LDOS), can serve as either a “relay station” to facilitate carrier tunneling or as a scattering center that reduces source-drain currents. This work hence provides valuable insights into the doping effect of short-channel 2D transistors, and opens up possibilities for new electronic applications that harness the delicate properties of these substitutional dopants.