Controllable growth of bilayer WS2 by chemical vapor deposition and application for photodetectors

• Bilayer WS 2 was achieved by simple spin-coating and finely controlling the time of introducing sulfur. • The as-grown bilayer WS 2 exhibits good crystallinity with AA stacking. • Photodetector based on the bilayer WS 2 shows good performance. WS 2 is a promising material in the next generation integrated circuit applications and its electrical and optoelectronic characteristics is dependent on the number of layers. Here, a simple and scalable synthesis of WS 2 bilayers via chemical vapor deposition (CVD) is demonstrated by finely controlling the time of introducing sulfur. The optical and microstructural characterization of the as-grown bilayer WS 2 show a uniform single crystal quality. The photodetector based on bilayers WS 2 exhibits relatively good performance.