Ultrathin SnS2 nanosheets of ultrasonic synthesis and their photoresponses from ultraviolet to near-infrared

Ultrathin SnS2 nanosheets are synthesized for the first time by a simple ultrasonic method, and then fabricated onto a SiO2/Si substrate to form nanosheet-based phototransistor which exhibits a broad photoresponse from 254 to 980 nm, dependence of photocurrent on optical power and wavelength, fast-response, and long-term stability. Under illumination of 532-nm light with an optical power of 19.3 mW/cm2 (0.68 nW), the photoswitch current ratio (PCR) is about 8.7, while the photoresponsivity, external quantum efficiency, and detectivity are 0.65 mA/W, 0.15%, and 1.13 × 108 J, respectively. Compared with the reported SnS2-based photodetectors, the SnS2-nanosheet phototransistor shows an enhanced photosensitive performance.