Nonmetal‐Mediated Atomic Spalling of Large‐Area Monolayer Transition Metal Dichalcogenide

Abstract

Transition metal dichalcogenides (TMDCs) have attracted intense interest; however, despite the considerable effort of researchers, a universal manufacturing method that can guarantee both high material quality and throughput has not been realized to date. Herein, a universal approach to producing high‐quality monolayer TMDCs on a large scale via germanium (Ge)‐mediated atomic spalling is presented. Through the modified analytic model, the study verifies that the thin Ge film could be a suitable stressor that effectively reduces the crack propagation depth at the sub‐nanometer range. In particular, an acid‐etching process is not required in the overall atomic spalling process due to the water‐soluble nature of the Ge, enabling it widely applicable to various TMDCs. Under the optimized spalling conditions, a millimeter‐sized monolayer of stable MoS2, as well as unstable MoTe2, is successfully achieved. Through detailed spectroscopic and electrical characterizations, it is confirmed that the proposed methodology for obtaining large‐area atomic layers does not introduce any significant structural defects or chemical contaminations.