Effect of holding time on the growth of two-dimensional molybdenum disulfide

The work aims to study the growth law of two-dimensional MoS2 flakes, and provide theoretical reference and technical experience for the future growth of transition metal chalcogenide films. MoS2 flakes were prepared by chemical vapor deposition (CVD), only the holding time of MoS2 flakes growth was changed. The growth rule of MoS2 flakes was investigated by optical microscopy, scanning electron microscopy (SEM) and Raman spectrum analysis. The results showed that the MoS2 flakes gradually grew from the initial nucleation point to a triangle with bright spots at the center (the wave number difference of Raman spectrum characteristic peak for MoS2 nucleation point was 20.25 cm−1) and further grew into a complete triangular MoS2 flakes (the wave number difference of Raman spectrum characteristic peak was 18.32 cm−1). With the extension of the holding time, filming between the MoS2 flakes began to splice, and finally nucleated on top of the film to grow bulk MoS2 flakes. The growth pattern of two-dimensional MoS2 flakes varies with the growth stage. The nucleation point is initially generated in a non-two-dimensional growth mode, and the non-nucleation point region is grown in a two-dimensional growth mode. During the continuous growth period, the MoS2 flakes were dominated by the two-dimensional growth pattern. In the splicing phase, multiple layers of MoS2 regions have emerged. In the second layer, the MoS2 flakes grow in a three-dimensional growth mode. © 2020, Chongqing Wujiu Periodicals Press. All rights reserved.