Controlled crack propagation for atomic precision handling of wafer-scale two-dimensional materials

Abstract

Although flakes of two-dimensional (2D) heterostructures at micrometer scale can be formed with adhesive-tape methods, isolation of 2D flakes into monolayers is extremely time-consuming as it is a trial-and-error process. Controlling the number of 2D layers through direct growth also presents difficulty because of the high nucleation barrier on 2D materials. We demonstrate a layer-resolved 2D material splitting technique that permits the high-throughput production of multiple monolayers of wafer-scale (5 centimeter diameter) 2D materials by splitting single stacks of thick 2D materials grown on a single wafer. Wafer-scale uniformity of h-BN, WS2, WSe2, MoS2, and MoSe2 monolayers was verified by photoluminescence (PL) response and by substantial retention of electronic conductivity. We fabricated wafer-scale van der Waals heterostructures, including field-effect transistors, with single-atom thickness resolution.