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

Abstract

The synthesis of few-layer tungsten diselenide (WSe₂) 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 WSe₂ with wafer-scale thickness and electrical uniformity is synthesized through direct selenization of thin films of e-beam evaporated W on SiO₂ 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 WSe₂ films demonstrate uniform electrical performance across the substrate. The intrinsic field-effect mobility of the films at a carrier concentration of 3 × 10¹² cm⁻² is 10 cm² V⁻¹ s⁻¹. The unprecedented uniformity of the WSe₂ on wafer-scale substrates provides a substantial step towards producing manufacturable materials that are compatible with conventional semiconductor fabrication processes.