All van der Waals Semiconducting PtSe₂ Field Effect Transistors with Low Contact Resistance Graphite Electrodes

Abstract

Contact resistance is a multifaceted challenge faced by the 2D materials community. Large Schottky barrier heights and gap-state pinning are active obstacles that require an integrated approach to achieve the development of high-performance electronic devices based on 2D materials. In this work, we present semiconducting PtSe₂ field effect transistors with all-van-der-Waals electrode and dielectric interfaces. We use graphite contacts, which enable high ION/IOFF ratios up to 10⁹ with currents above 100 μA μm⁻¹ and mobilities of 50 cm² V⁻¹ s⁻¹ at room temperature and over 400 cm² V⁻¹ s⁻¹ at 10 K. The devices exhibit high stability with a maximum hysteresis width below 36 mV nm⁻¹. The contact resistance at the graphite-PtSe₂ interface is found to be below 700 Ω μm. Our results present PtSe₂ as a promising candidate for the realization of high-performance 2D circuits built solely with 2D materials.