Topological van der Waals Contact for Two-Dimensional Semiconductors

Abstract

The relentless miniaturization inherent in complementary metal-oxide semiconductor technology has created challenges at the interface of two-dimensional (2D) materials and metal electrodes. These challenges, predominantly stemming from metal-induced gap states (MIGS) and Schottky barrier heights (SBHs), critically impede device performance. This work introduces an innovative implementation of damage-free Sb2Te3 topological van der Waals (T-vdW) contacts, representing an ultimate contact electrode for 2D materials. We successfully fabricate p-type and n-type transistors using monolayer and multilayer WSe2, achieving ultralow SBH (∼24 meV) and contact resistance (∼0.71 kΩ·μm). Simulations highlight the role of topological surface states in Sb2Te3, which effectively mitigate the MIGS effect, thereby significantly elevating device efficiency. Our experimental insights revealed the semiohmic behavior of Sb2Te3 T-vdW contacts, with an exceptional photoresponsivity of 716 A/W and rapid response times of approximately 60 μs. The findings presented herein herald topological contacts as a superior alternative to traditional metal contacts, potentially revolutionizing the performance of miniaturized electronic and optoelectronic devices.