Phase and Carrier Polarity Control of Sputtered MoTe₂by Plasma-induced Defect Engineering

Being able to precisely control the carrier polarity and conductivity plays a vital role while developing future two-dimensional (2D) transition metal dichalcogenides (TMDs)-based devices. Achieving such controllability in TMD material, however, remains challenging as a result of the strong Fermi-level pinning with contact metals [1]. MoTe 2 , one of the group-VI TMDs, has high mobility, a moderate bandgap, and the lower energy difference between polymorphic semiconducting 2H and metallic 1T' phases, allowing versatile electrical properties. It's known that controlling the number of chalcogen defects in TMD considerably alters its electrical characteristics [2] , [3]. In this study, we report the results of engineering Te defects in MoTe 2 by plasma treatment where (1) 2H phase is stable at a Te/Mo ratio between 1.88 and 2.13, and (2) MoTe 2 transistors can be converted from p- to n-type conduction by the defect-induced conduction band edge (CBE) lowering.