Tunable Gain SnS₂/InSe Van der Waals Heterostructure Photodetector

Due to the favorable properties of two-dimensional materials such as SnS_2, with an energy gap in the visible light spectrum, and InSe, with high electron mobility, the combination of them can create a novel platform for electronic and optical devices. Herein, we study a tunable gain SnS₂/InSe Van der Waals heterostructure photodetector. SnS₂ crystals were synthesized by chemical vapor transport method and characterized using X-ray diffraction and Raman spectroscopy. The exfoliated SnS₂ and InSe layers were transferred on the substrate. This photodetector presents photoresponsivity from 14 mA/W up to 740 mA/W and detectivity from 2.2 × 10⁸ Jones up to 3.35 × 10⁹ Jones by gate modulation from 0 V to +70 V. Light absorption and the charge carrier generation mechanism were studied by the Silvaco TCAD software and the results were confirmed by our experimental observations. The rather high responsivity and visible spectrum response makes the SnS₂/InSe heterojunction a potential candidate for commercial visible image sensors.