CVD Growth of Uniform and Continuous MoS2 Atomic Layers
Yu-Hao Chan1*, Pei-Chin Lee1, Tzu-Hsien Shen1, Cheng-Yen Wen1
1Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
* presenting author:Yu Hao Chan, email:cp50810@gmail.com
Single-layered two-dimensional (2D) materials offer the possibilities of minimizing semiconductor devices down to the atomic scale. The MoS2 monolayer, which has a direct bandgap of 1.8 eV, has attracted much attention in experimental and theoretical researches for applications of MoS2 monolayers on optoelectronic devices, field effect transistors, low power switches, valleytronics, etc. For practical application of MoS2 monolayers on these devices, it is of importance to develop a reliable growth to synthesize large-area, uniform, and continuous MoS2 monolayers. Here we present a method of growing high-quality MoS2 atomic layers using the chemical vapor deposition process. In this method, the precursors, MoO3 and sulfur, are carried by high-purity argon into the silicon oxide substrates in the furnace. The growth temperature is 700°C. Uniform and continuous MoS2 films can be obtained on SiO2 substrate in a size of 1×1 cm2, as observed using scanning electron microscopy (SEM). We characterized MoS2 films using Raman and Photoluminescence (PL) spectroscopy. In Raman analysis, the separation between the E2g and A1g peaks is 21.34 cm-1, indicating more than one layers of MoS2 are deposited on the substrate, consistent with the PL results, in which a peak at 651 nm is shown. Microstructure analysis using scanning transmission electron microscopy (STEM) shows that the MoS2 thin films are continuous and the number of layers is approximately 3~4. Simultaneous multilayer growth of MoS2 layers is observed. It is suggested that reducing the nucleation on the top surface of a growing MoS2 layer while continuing lateral growth would be helpful to synthesize the MoS2 monolayer.


Keywords: Two-dimensional (2D) materials, MoS2, Microstructure analysis, Large-area, Uniform, and Continuous