Effects of Strategically Placed Water Droplets on Monolayer Growth of Molybdenum Disulfide

Figure 2

Optical images of the surface of CVD-grown monolayers and multilayers of MoS₂ on SiO₂/Si substrate using different volumes of water on growth substrates and in MoO₃ source. The droplets had different positions on the substrates, with each droplet representing a certain volume of water. The insets show the corresponding enlarged optical images of the surface after MoS₂ growth. Red squares on the substrates indicate the region of samples from where the optical images showing MoS₂ growth was obtained. Symmetric and asymmetric water distributions represent the water droplet position with respect to the center of MoO₃ source. The dashed lines on the optical images indicate the contour of water droplets. Scale bar and ratio of water on Si and in MoO₃ are (a) 10 μm, 0/0; (b) 100 μm (inset 10 μm), 60/5; (c) 40 μm, 20/50; and (d) 20 μm, 0/200.