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

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.