11:00 〜 11:15
▲ [15a-2J-6] Effect of WO3 precursor and sulfurization process on WS2 crystals growth by atmospheric pressure CVD technique
キーワード：dichalcogenides,chemical vapor deposition,ramping rate
Individual monolayers of metal dichalcogenides are atomically thin two-dimensional crystals have attracted significant interest owing to their direct-bandgap property for nano electronics and optoelectronics applications. In this prospect, controllable synthesis of high quality WS2 crystals by a chemical vapor deposition (CVD) process is of great importance. Here, we report the effect of sulfurization process and WO3 precursor on WS2 growth in an atmospheric pressure (AP) CVD. S powder was placed in the center of low temperature furnace and the WO3 (2 and10 mg) powder spread on SiO2/Si substrate, which was kept in the small ceramic tube and placed in the center of high temperature furnace. S vapor was introduced with Ar flow rate of 80 sccm. Subsequently, the temperature of growth zone (SiO2/Si substrate with WO3 powder) was increased upto 750ºC by the ramping rate 3ºC min-1. The quantity of WO3 powder spread on SiO2/Si substrate significantly affect the nucleation and layer numbers of triangular-shaped WS2 crystals. Pyramid-like few-layers stacked structure of WS2 crystals are obtained from densely spread WO3 powder, whereas larger triangular crystals (~70 mm) are obtained by controlling the amount of WO3 precursor and rate of sulfurization at 750°C.