Single‐Step Synthesis of In‐plane 1T'‐2H Heterophase MoTe ₂ for Low‐Resistance Contacts

Abstract MoTe 2 possesses two polymorphs: semiconducting (2H) and semi‐metallic (1T') phases, separated by a small energy barrier. The 1T' phase of MoTe 2 provides an excellent platform for forming low‐resistance contacts with the 2H phase, where the low density of states in the semimetal suppresses metal‐induced gap states (MIGS) and reduces Fermi‐level pinning. However, existing fabrication methods encounter significant challenges in location control, contact quality, and device scaling. In this work, a new method is developed to synthesize 1T'‐2H heterophase structures using chemical vapor deposition (CVD). By depositing pre‐patterned molybdenum, seamless in‐plane 1T'‐2H MoTe 2 heterophase junctions are synthesized in a single‐step process, achieving precise control over the location of each phase and uniform MoTe 2 coverage across centimeter‐scale surfaces. Field‐effect transistors incorporating 1T' MoTe 2 contacts and 2H MoTe 2 channels show p‐type dominant transfer characteristics and exceptionally low contact resistance. The unique attributes of these 1T' MoTe 2 contacts, including pristine interfaces, reduced Schottky barrier heights, and seamless edge contacts, combined with the pronounced ambipolarity of the grown 2H MoTe 2 , demonstrate the commercial viability of this process for 2D transistors, addressing the long‐standing challenge of contact resistance in 2D transistor technology.