Enhancement of WSe2 FET Performance Using Low-Temperature Annealing

Abstract

In this study, we investigate a non-thermal annealing process for two-dimensional materials. Instead of high temperature, we exploit the electron wind force at near-room temperature conditions. It is an atomic-scale mechanical force that acts only in the defective regions, which is proposed to provide very high defect mobility. The process is demonstrated on back-gated WSe2 transistors. Electron wind force annealing was performed by passing current through the device channel while actively removing the Joule heating. We observe approximately one order of magnitude increase in the drain current, validating our hypothesis on the mobility imparted by the electron wind force to migrate and eliminate defects. To explain the atomistic mechanisms behind the room-temperature annealing, we perform molecular dynamics simulation. Computational evidence of defects annihilation and local metallic phase transformation supports the experimental results, which can enhance the device performance. Further developments of the proposed technique will potentially lead to time- and cost-effective post-processing of two-dimensional materials-based devices.