Manipulation of the 1T-MoS2 domain in a 2H-MoS2 main phase induced by V-doping via a CVD vapor–liquid–solid mechanism

Abstract

Exhaustive research of phase engineering of two-dimensional molybdenum disulfide (2D-MoS₂) is currently ongoing to develop numerous applications, including optoelectronic devices, spintronics, and new platforms for the study of unconventional quantum phenomena. Therefore, it is urgently needed to achieve phase-controlled synthesis of MoS₂ with a high quality and large area. However, the metallic phase MoS₂ (1T-MoS₂) synthesized by conventional chemical vapor deposition (CVD) is randomly distributed in the semiconductor phase (2H-MoS₂) domain, and the position-controlled synthesis of the phase is not achieved. In this study, we achieved the controlled synthesis of the 1T-MoS₂ domain in the 2H main phase. Salt-assisted CVD was used to induce V-atom doping at the right time by controlling the concentration of vanadium ions. The synthesis benefitted from 1D vapor–liquid–solid (VLS) growth and 2D vapor–solid (VS) edge expansion. The results of the growth controlled by regulating the NaCl concentration showed that the 1T phase was located at the three vertex domains of the MoS₂ triangle. The distribution domains of 1T phase MoS₂ can be confirmed by Raman mapping, X-ray photoelectron spectroscopy, and transmission electron microscopy. Furthermore, we calculated the doping rate of V atoms in VLS and VS modes based on the two-dimensional diffusion model and observed that the doping rate of V atoms in the VLS mode was approximately three times higher than that in the VS mode, which was consistent with the experimental results. The controllable phase-domain synthesis of 2D-MoS₂ is beneficial to the preparation of nano-electronic devices and provides a platform for the study of physicochemical properties.