Wafer-Scale Bi-Assisted Semi-Auto Dry Transfer and Fabrication of High-Performance Monolayer CVD WS2 Transistor

Abstract

A novel wafer-scale semi-automated dry transfer process for monolayer (1L) CVD WS2 was developed utilizing the weakly coupled interface between semimetal (Bi) and two-dimensional (2D) semiconductor (WS2). Bi semimetal serves as a gently adhesive transfer template for 2D materials, introducing minimal additional defects during the transfer process. Based on 2D materials processed using this new transfer method, semimetal-contacted (Bi and Sb) monolayer CVD WS2 nFETs were further demonstrated at wafer scale. Our CVD 1L WS2 nFETs fabricated using semimetal-assisted transfer with semimetal (Bi and Sb) contacts show record high on-current of 250 µA/µm and 243 µA/µm at VDS = 1 V, and record low contact resistance of 0.63 kΩ•µm and 0.73 kΩ•µm, respectively.