One-Step Synthesis of Two-Dimensional Metal-Semiconductor Circuitry Based on W-Triggered Spatial Phase Engineering

Molybdenum ditelluride (MoTe₂) exhibits a variety of crystal phases, which can be phase-controlled by various external means, showing broad prospects in modern integrated circuits. The structure in which the semimetal 1T′ (or T_d) phase electrode contacts the semiconductor 2H phase channel is considered an elegant solution for high-performance two-dimensional (2D) circuits because it achieves low contact resistance. However, most of the 2D metal-semiconductor structures for large-area integration use a two-step growth process, which puts forward high requirements for the secondary growth compatibility of the material. Here, we develop a method for the stable synthesis of the metallic Mo_xW_1-xTe₂ (0 < x < 1) by W-triggered spatial phase engineering, and we further obtain a large-area Mo_xW_1-xTe₂/2H-MoTe₂ in-plane metal-semiconductor structure by one-step tellurization of a MoW/Mo periodic structure. Due to the unique 2D in-plane epitaxial mechanism of the phase transition from 1T′ to 2H, the highly crystalline semiconductor 2H-MoTe₂ squeezes between two metallic Mo_xW_1-xTe₂ electrodes and forms a seamless coplanar contacted channel; thus, the fabricated field-effect transistors exhibit good electrical characteristics. In addition, large-area 2D metal-semiconductor heterostructure arrays can be transferred onto flexible substrates, showing promising applications in flexible electronics. Herein, one-step synthesis of large-area 2D in-plane metal-semiconductor arrays opens up new possibilities for future integrated high-performance logic circuits.