Controlled growth of high spatial uniformity of monolayer single crystal MoS2

MoS2 nano-films have attracted extensive interest from scientists owing to its unique material properties with adjustable bandgap structure and broad application prospects in electronic and optoelectronic devices. Herein, we report a chemical vapor deposition method based on adjusting the relative position of the molybdenum source and SiO2/Si substrates to control MoO3 concentration adsorbed on the surface of substrate to achieve the controlled growth of monolayer single crystal MoS2 with spatial uniformity and low nucleation density. Moreover, optical microscopy, Raman, photoluminescence, atomic force microscopy and transmission electron microscope were employed to characterize the uniformity and crystal quality of the grown monolayer MoS2. The measurement results show that the triangle side length of a single MoS2 film can reach 110 μm. And the I-V switching ratio of the back-gate field effect transistors based on growing MoS2 is 6.3 × 108, which is equivalent or slightly higher than that of other CVD-grown samples. Besides, growth mechanism of MoS2 was further investigated, combining the substrate position with concentration of MoO3 deposited on the surface of substrate. This work is of great benefit to the controlled growth of other two-dimensional materials and uniform performance of multiple electronic array devices.