Field-effect transistors based on wafer-scale, highly uniform few-layer p-type WSe2

The synthesis of few-layer tungsten diselenide (WSe 2 ) via chemical vapor deposition typically results in highly non-uniform thickness due to nucleation initiated growth of triangular domains. In this work, few-layer p-type WSe 2 with wafer-scale thickness and electrical uniformity is synthesized through direct selenization of thin films of e-beam evaporated W on SiO 2 substrates. Raman maps over a large area of the substrate show small variations in the main peak position, indicating excellent thickness uniformity across several square centimeters. Additionally, field-effect transistors fabricated from the wafer-scale WSe 2 films demonstrate uniform electrical performance across the substrate. The intrinsic field-effect mobility of the films at a carrier concentration of 3 × 10 12 cm −2 is 10 cm 2 V −1 s −1 . The unprecedented uniformity of the WSe 2 on wafer-scale substrates provides a substantial step towards producing manufacturable materials that are compatible with conventional semiconductor fabrication processes. This work demonstrates the synthesis of large-area WSe 2 with excellent uniformity across the wafer scale.