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.