Effect of growth temperature on the morphology control and optical behavior of monolayer MoS 2 on SiO 2 substrate

Chemical vapor deposition (CVD) is a promising method for producing high-quality two-dimensional (2D) transition metal dichalcogenides (TMDs) over large area. In this paper, we report the effect of temperature on the shape evolution of monolayer-thick molybdenum disulfide (MoS 2 ) grown by CVD on SiO 2 /Si substrate. As in our previous study (ref. 22), the substrate is placed slightly upstream to the Mo source on a barrier where the vapor concentration is optimum for a homogeneous MoS 2 formation. Three distinct grain shapes (equilateral triangle, edge-curved triangle, and circle) evolved as a result of change in growth temperature from 725–775 °C. Circular MoS 2 grains, emerged due to substrate (SiO 2 /Si) influence at a growth temperature of 775 °C, exhibited strong photoluminescence compared to other shapes. We also demonstrated formation of continuous monolayer MoS 2 by prolonging the growth duration. The findings of the present study provide insight into the nucleation and growth kinetics of MoS 2 on SiO 2 /Si substrate under the influence of growth temperature.