Flow Rate-Driven Morphology Evolution of Chemical Vapor Deposited WS2 at Varying Temperatures

Due to its unique electronic and optical properties, tungsten disulfide (WS2) is a promising material for various device applications. However, achieving an efficient and cost-effective method for synthesizing large-area uniform WS2 is still challenging. In this work, we demonstrate the synthesis of few-layer WS2 crystallites by NaCl-assisted low-pressure chemical vapor deposition and study the effect of temperature and the carrier gas flow rate on the morphology, structure, and optical properties of the as-grown WS2 films. We observe transitions between regular triangular to strongly disordered structures with sizes up to 50 µm through temperature and carrier gas flow rate tuning. As-grown samples were characterized by Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The result of this work provides a path toward the optimization of growth conditions for obtaining WS2 with desired morphologies for various applications.