2D 半导体隧穿极限的 ab initio 传递长度法仿真

随着半导体器件逼近亚 2 nm 工艺节点，确定接触电阻尺度的量子机械极限变得至关重要;然而，在这一深纳米尺度 regime 中，从热电子辐射向直接隧穿的转变仍然无法通过实验获得，也没有被理论定义。Herein, we present a systematic first-principles framework to characterize metal/2D-semiconductor interfaces at the atomic scale and identify their intrinsic contact resistance and tunneling limits. Based on large-scale multi-space density functional theory calculations, we perform ab initio transmission line model (TLM) analyses for monolayer MoS2 contacted by Sc, Ag, Au, and Pd electrodes in both top-contact and edge-contact geometries. This computational procedure reveals a universal transition in resistance scaling from metal-induced gap states-mediated direct tunneling in the sub-10 nm regime to thermionic emission at longer channel lengths. The resulting transition length provides a rigorous first-principles measure of the critical tunneling length, establishing a physically grounded metric for assessing contact quality and the source-to-drain tunneling limit of 2D ballistic transistors. Using the ab initio TLM method, we further identify optimal contact strategies-top contact with low-work-function metals for n-type operation and edge contact with high-work-function metals for p-type operation. Our study introduces a general computational framework for evaluating and comparing 2D semiconductor contacts and offers practical guidelines for engineering low-resistance, scalable contact technologies for next-generation 2D transistors.