Topological van\nder Waals Contact for Two-Dimensional\nSemiconductors

The relentless miniaturization inherent in complementary\nmetal-oxide\nsemiconductor technology has created challenges at the interface of\ntwo-dimensional (2D) materials and metal electrodes. These challenges,\npredominantly stemming from metal-induced gap states (MIGS) and Schottky\nbarrier heights (SBHs), critically impede device performance. This\nwork introduces an innovative implementation of damage-free Sb<sub>2</sub>Te<sub>3</sub> topological van der Waals (T-vdW) contacts,\nrepresenting an ultimate contact electrode for 2D materials. We successfully\nfabricate p-type and n-type transistors using monolayer and multilayer\nWSe<sub>2</sub>, achieving ultralow SBH (∼24 meV) and contact\nresistance (∼0.71 kΩ·μm). Simulations highlight\nthe role of topological surface states in Sb<sub>2</sub>Te<sub>3</sub>, which effectively mitigate the MIGS effect, thereby significantly\nelevating device efficiency. Our experimental insights revealed the\nsemiohmic behavior of Sb<sub>2</sub>Te<sub>3</sub> T-vdW contacts,\nwith an exceptional photoresponsivity of 716 A/W and rapid response\ntimes of approximately 60 μs. The findings presented herein\nherald topological contacts as a superior alternative to traditional\nmetal contacts, potentially revolutionizing the performance of miniaturized\nelectronic and optoelectronic devices.