Tungsten disulfide (WS2) has an important attention owing to its layer-dependent unique properties. In the monolayer form, it is easily grown via chemical vapor deposition (CVD). The morphological and structural properties could be importantly moderated via CVD growth parameters. In the present study, we report a methodology for the fabrication of high-quality WS2 monolayers using a single-zone CVD system. The primary objective of the work is to investigate the effect of CVD experimental process parameters on the lateral size, morphology, and crystal quality of WS2 monolayers. The topographic, structural, and optical properties of WS2 monolayer were investigated by optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, and photoluminescence (PL). In the present study, the best CVD growth parameters for the better crystallinity and bigger lateral size were determined to be a WO₃ precursor amount of 5 mg WO₃, an Ar carrier a gas flow of 25 sccm, a growth temperature of 850 °C, a growth time of 4 min, and a distance of the sulfur source to the furnace centre of 18.5 cm. As a result of CVD parameter optimization, the large-lateral-sized monolayer WS2 material with a lateral length of ~ 80 µm was easily and cheaply deposited. As it is well known, device applications of such materials are severely limited by the inability to produce high-quality and large size. Our results show that the improved surface integrity of optimized monolayer WS₂ flakes holds promise for device fabrication.
Küçük et al. (Mon,) studied this question.