Enhanced Photoresponse of Indium-Doped Tin Disulfide Nanosheets

Doping of tin disulfide (SnS2) is an effective strategy to regulate its physical and chemical properties. In this work, In doping was used to manipulate the photoresponse behavior of SnS2-based photodetectors. In-doped SnS2 nanosheets were synthesized via a facile hydrothermal method. It was found that the In doping concentration plays an important role in the size of the fabricated SnS2 nanosheets. With the increase in the In doping concentration, the lateral size of samples increased from ∼210 to ∼420 nm, but the crystallinity became poor at higher concentrations. Energy dispersive X-ray-mapping results show that the In was homogeneously distributed in the samples. In addition, a red shift was observed in the binding energy of Sn and S with increased In doping concentration, which may be due to the p-type doping of In in SnS2. After In doping, the performance of SnS2-based photodetectors was significantly improved. The photoresponse speed of In-doped SnS2-based photodetectors was faster than that of pristine SnS2-based devices under the illumination of 532 and 405 nm lasers. This work develops an effective approach of In doping to enhance the photoresponse characteristics of SnS2-based photodetectors and proves that In-doped SnS2 has a vast potential in optoelectronic applications.