Selective Charge Injection via Topological van der Waals Contacts for Barrier‐Free p ‐Type TMD Transistors

Abstract The continued miniaturization of electronic and optoelectronic devices places stringent demands on contact engineering for 2D semiconductors, particularly for p ‐type materials, where achieving low‐resistance contacts remains a critical challenge. While van der Waals (vdW) contacts offer a promising route for next‐generation electronics, the impact of microscopic interfacial phenomena on device performance remains insufficiently understood. Here, how selective charge injection is revealed to be governed by key interfacial parameters between WTe 2 , a topological vdW contact, and both Se‐ and S‐based transition metal dichalcogenide (TMD) channel materials. Through device measurements and first‐principles simulations, it is shown that WTe 2 forms an exceptional vdW contact with p ‐type MoSe 2 , exhibiting an ultralow Schottky barrier height (≈7 meV), low contact resistance (≈0.47 kΩ µm), and high carrier mobility (373 cm 2 V −1 s −1 ). This selective charge injection is attributed to a larger interlayer distance in WTe 2 /Se‐based TMDs, which suppresses orbital overlap and preserves interface quality. These microscopic descriptors serve as essential design principles for future 2D electronic and optoelectronic systems.