High-conductance Two-dimensional 1T '-MoTe2 Synthesized by Sputtering

Abstract

Among extensively researched 2D-TMDs, MoTe2 is an emerging but understudied material because of the lack of reliable and reproducible synthesis methods. The difficulties of its synthesis originate from the weak Mo-Te bonding energy, which results in the low chemical reactivity of MoTe2. Additionally, compared with other TMDs, MoTe2 is relatively unstable. It easily oxidizes and decomposes at high temperatures, which complicate the synthesis using conventional CVD. We have previously developed a PVD method capable of depositing large-area, high-crystallinity, few-layer 2D MoTe2 without complex designs of gas-phase transport or Mo-Te chemical reaction. MoTe2 is directly sputtered and post-annealed in a 2D encapsulation structure to improve its crystallinity. MoTe2 can be synthesized in either homogeneous semiconducting 2H or metallic 1T' phase by controlling the adequate thermal budget during annealing. This talk will mainly discuss the process optimization and electrical properties of 1T'-MoTe2, which is potentially important in several emerging research fields, including 2D interconnect, topological superconductor, and 2H-1T' in-plane homojunction transistor.