Controllable synthesis and optoelectronic applications of wafer-scale MoS2 films

The chemical vapor deposition (CVD) method is widely used for synthesizing two-dimensional (2D) materials such as molybdenum disulfide (MoS2) because of the process’ simplicity, relatively low cost, compatibility with other process, and tendency to result in high-quality crystalline materials. However, the growth of films with a uniform large area of several square centimeters with control of the number of layers remains challenging. Here, a MoS2 synthesis technique that enables thickness and size control of wafer-scale films with high uniformity and continuity is proposed. This CVD technique is a powerful and simple method to control the layer number and size of MoS2 films without using additive chemicals or a complex process. The thickness of the MoS2 films can be controlled from one to four layers by adjusting the concentration of MoO3. MoS2 films with dimensions greater than 10 cm can be grown by manipulating the Ar/H2S ratio. In addition, a photodetector based on CVD-grown MoS2 is shown to exhibit a high current on–off ratio of 105 and gate-tunability. It also shows a high responsibility of 1.2 A W−1, external quantum efficiency of 345%, and a specific detectivity of 1.2 × 1011 Jones. The proposed CVD technique can provide a facile direction for the controllable synthesis of wafer-scale MoS2 films with diverse applications in future optoelectronic devices.