Facile synthesis of tin monosulfide nanosheets via physical vapour deposition and their near-infrared photoresponse

Two-dimensional layered materials (TDLMs), such as tin sulfide (SnS2), have attracted significant attention due to their vast potential applications in the fields of electronics, optoelectronics, energy conversion, and storage. Tin monosulfide (SnS) is an intrinsic p-type semiconductor in the family of TDLMs. Further explorations of SnS requires the development of efficient synthesis techniques. Here, we report SnS nanosheets grown via a physical vapour deposition (PVD) approach. The morphology was characterized using Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). These SnS nanosheets exhibit a square shape with a smooth surface having an average lateral size of 7 μm and a thickness of 12 nm. No impurities were observed in the SnS nanosheets. Furthermore, photodetectors based on such SnS nanosheets were fabricated. The results show that the as-grown SnS has an excellent photo-response performance for an 850-nm laser with a high responsivity of 1604 AW-1, an external quantum efficiency of 2.34 × 105% and a detectivity of 3.42 × 1011 jones, which are larger than those values reported for previous SnS-based photodetectors. Moreover, the rise and fall times are 7.6 and 29.9 ms, respectively. Our work provides a strategy to obtain high-purity and ultrathin SnS while indicating that SnS has a great potential in applications for near-infrared photodetectors.