Quantum Transport in Two-Dimensional WS₂ with High-Efficiency Carrier Injection through Indium Alloy Contacts

Abstract

Two-dimensional transition metal dichalcogenides (TMDCs) have properties attractive for optoelectronic and quantum applications. A crucial element for devices is the metal-semiconductor interface. However, high contact resistances have hindered progress. Quantum transport studies are scant as low-quality contacts are intractable at cryogenic temperatures. Here, temperature-dependent transfer length measurements are performed on chemical vapor deposition grown single-layer and bilayer WS₂ devices with indium alloy contacts. The devices exhibit low contact resistances and Schottky barrier heights (∼10 kΩ μm at 3 K and 1.7 meV). Efficient carrier injection enables high carrier mobilities (∼190 cm² V^-1 s^-1) and observation of resonant tunnelling. Density functional theory calculations provide insights into quantum transport and properties of the WS₂-indium interface. Our results reveal significant advances toward high-performance WS₂ devices using indium alloy contacts.