Controllable synthesis and optoelectronic applications of wafer-scale MoS2 films

Abstract

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.