Janus metal-enabled tunable Schottky barriers in van der Waals contacts via interfacial polarization modulations

Abstract

Two-dimensional semiconductors exhibit exceptional potential in next-generation electronics; however, the strong Fermi-level pinning effect in the metal–semiconductor (M–S) contacts inevitably generates an unmodulated Schottky barrier, severely compromising device performance. Here, to address this challenge, we propose a novel strategy using the polar metallic Janus TaSTe originating from the broken structure symmetry. Specifically, by switching the S or Te surface in contact with a semiconductor, tunable M–S interface interactions have been effectively achieved by the Janus TaSTe electrode, which is determined by interfacial polarization due to the difference in the electronegativity of S and Te atoms. In addition, we show that under the external electric fields and strain, the heights and types of the Schottky barrier of Janus TaSTe–PtS₂ contact have been effectively tuned. We further demonstrate the universality of our strategy by expanding various M–S contacts between different Janus metals and semiconductors. Our results break through the limitation of work function and provide a novel way to tune the interfacial interactions between the metal and semiconductors, holding promising applications for future high-performance electronic devices.