Broadband self-powered photodetector based on the large-area continuous WS0.9Se1.1 film

The thickness and area of WS 2 are critical for the optoelectronic response and bandgap. It is necessary to develop a large-area WS 2 with an adjustable bandgap to obtain a high-performance optoelectronic device. In this work, large-area continuous WS (2-2x) Se 2x ( x  = 0, 0.265, 0.39, 0.55) thin films were synthesized by the chemical vapor deposition . The bandgap range was adjusted by controlling the selenization time. Furthermore, the photodetectors Ag/WS (2-2x) Se 2x /Ag with different Se compositions were explored. And a high-performance photodetector Ag/WS 0.9 Se 1.1 /Ag was constructed with a wide detection range of ultraviolet–visible–near infrared band. The responsivity, specific detection, and on/off ratio are 1.5 A/W,1.20 × 10 11 Jones, and 2.9 × 10 5  at 365 nm, and the response time is 1.92 μs. This work provided a new synthetic method for growing bandgap-tunable transition metal disulfide and a new option for photoelectric detection in the ultraviolet–visible–near infrared region.