Ni-assisted crystallization of few-layer transition metal dichalcogenide ultra-thin films

Two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors have received tremendous attention in various research fields in recent years. Different synthetic approaches to grow large-scale TMD thin films have been widely explored for effective device integration and circuit-level applications. However, the poor crystalline quality of most synthesized TMD films has seriously restricted their further implementation in high-performance nanoelectronic devices. Here, we demonstrated a Ni-assisted synthesis of TMD films based on atomic layer deposition. Two crystallization mechanisms have been studied: metal-induced crystallization and metal-induced lateral crystallization. The involvement Ni has significantly lowered the crystallization temperature in both cases and the crystallinity of TMD films has been greatly enhanced which is confirmed by Raman and X-ray photoelectron spectroscopy characterizations. Our results can pave the way for advanced applications of high-quality large-area synthetic TMDs and device integrations with low temperature processes.