Device Transport\nCharacteristics of Monolayer SnS<sub>2</sub> and HfS<sub>2</sub> Field-Effect\nTransistors with Semimetal\nContacts

Atomically thin two-dimensional (2D) semiconductors with\nmoderate\nband gaps have shown great potential as semiconducting materials for\nconstructing high-performance transistors and integrated circuits.\nHowever, the untunable Schottky barrier height (SBH) and strong Fermi\nlevel pinning (FLP) at the metal/semiconductor interface result in\nsignificant contact resistance in 2D transistors, hindering device\nscaling and performance improvements. In this study, we present a\ncomprehensive analysis of the interface contact and device transport\nproperties between semimetallic bismuth (Bi), antimony (Sb), arsenic\n(As), and semiconducting monolayer SnS<sub>2</sub>, HfS<sub>2</sub>, and ZrS<sub>2</sub>. Our first-principles results demonstrate that\nideal n-type Ohmic contacts and small interlayer tunnel barriers can\nbe formed at the electrode/channel interfaces. Moreover, 5.1 nm SnS<sub>2</sub> FETs with direct Bi, Sb, and As electrode contacts exhibit\nultralow resistance values of 26.83–57.91 Ω μm\nand a high on-state current of 970.74–1640.74 nA/nm, satisfying\nthe application requirements of the International Roadmap for Devices\nand Systems (IRDS) for high-performance transistors in 2028. These\nfindings suggest that semimetals Bi, Sb, and As are potential electrode\nmaterials for ultrashort 2D transition metal dichalcogenide (TMDC)\nchannels and could benefit the design of high-performance transistors\nin the post-Moore era.