Highly Efficient\nElectrode of Dirac Semimetal PtTe<sub>2</sub> for MoS<sub>2</sub>‑Based\nField Effect Transistors

Two-dimensional van der Waals (vdW) layered materials\nnot only\nare an intriguing fundamental scientific research platform but also\nprovide various applications to multifunctional quantum devices in\nthe field-effect transistors (FET) thanks to their excellent physical\nproperties. However, a metal–semiconductor (MS) interface with\na large Schottky barrier causes serious problems for unleashing their\nintrinsic potentials toward the advancements in high-performance devices.\nHere, we show that exfoliated vdW Dirac semimetallic PtTe<sub>2</sub> can be an excellent electrode for electrons in MoS<sub>2</sub> FETs.\nHigh-performance FET characteristics reaching the FET mobility of\n85 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> are\nobserved with a negligibly small Schottky barrier height and large\non–off current ratio over 10<sup>8</sup>, which is among the\nhighest performances in reported electrodes for MoS<sub>2</sub>. Discussions\nare had on the reason that exfoliated PtTe<sub>2</sub> with Dirac\nstates shows highly efficient electrode performances based on the\ncomparisons with various other metal electrodes. The orbital hybrid\neffect between Dirac-semimetal PtTe<sub>2</sub> and MoS<sub>2</sub> was evidenced by the relative shift of Raman spectra peaks in the\nheterojunction, resulting in good ohmic contacts. These findings provide\nan important route to find high-performance electrodes for layered\nvdW materials and their related quantum devices.