Chemical Vapor Deposition Growth of Large-Area Monolayer MoS_2 and Fabrication of Relevant Back-Gated Transistor

A closed two-temperature-zone chemical vapor deposition (CVD) furnace was used to grow monolayer molybdenum disulfide (MoS_2) by optimizing the temperature and thus the evaporation volume of the Mo precursor. The experimental results show that the Mo precursor temperature has a large effect on the size and shape transformation of the monolayer MoS_2, and at a lower temperature of < 760^\circ\!C, the size of the triangular MoS_2 increases with the elevating temperature, while at a higher temperature of >760^\circ\!C, the shape starts to change from a triangle to a truncated triangle. A large-area triangular monolayer MoS_2 with a side length of 145 μm is achieved at 760^\circ\!C. Further, the as-grown monolayer MoS_2 is used to fabricate back-gated transistors by means of electron beam lithography to evaluate the electrical properties of MoS_2 thin films. The MoS_2 transistors with monolayer MoS_2 grown at 760^\circ\!C exhibit a high on/off current ratio of 10^6, a mobility of 1.92 cm^2/Vs and a subthreshold swing of 194.6 mV/dec, demonstrating the feasible approach of CVD deposition of monolayer MoS_2 and the fabrication of transistors on it.