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

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.