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 (similar to 10 k Omega mu m at 3 K and 1.7 meV). Efficient carrier injection enables high carrier mobilities (similar to 190 cm(2) 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.