Lithographically Defined Synthesis of Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) possess unique and highly tunable optoelectronic properties, but their large-scale fabrication and integration is still challenging. To address this problem, we developed a "lateral conversion" technique, which enables the synthesis of TMDs with predefined thickness and shape at specific locations on a wafer. The lateral conversion of metals, metal oxides, and nitrides into metal dichalcogenides resulted in few-layer TMDs covered with a capping layer. This layer protects the delicate TMD interfaces during subsequent fabrication steps from contamination, as well as improves their air stability. We demonstrated that lateral conversion can be used to synthesize various sulfides, selenides and tellurides, as well as alloys, lateral and vertical heterostructures. The patterned TMDs can be easily transferred from growth to device substrates or directly integrated into silicon-based CMOS platforms.