High-performance photodetection using one-step CVD-fabricated SnS/SnS₂ heterostructure film

Two-dimensional heterojunctions hold great promise for optoelectronic applications since the unique band structures and interfacial properties. However, conventional fabrication techniques suffer from problems like interface contamination, difficulties in scaling production, and poor process control, leading to degraded and unstable device performance. In this work, we develop a one-step in-situ chemical vapor deposition strategy for the controlled synthesis of high-quality SnS/SnS₂ heterostructures. This approach leverages the inherent process control to achieve clean interfaces and scalable production. The designed Au-SnS/SnS₂-Au sandwich heterostructure photodetector, comprising bulk SnS and ultrathin SnS₂, exhibits a dominant space-charge-limited current mechanism. With bidirectional bias applied, the photocurrent shows a superlinear increase, which is attributed to efficient carrier management behavior. Consequently, this device achieves superior photoresponse: the photoresponsivity of 119.1 mA/W, the detectivity of 5.73 × 10¹¹ Jones, and fast response speed of 16.8 ms. The study not only provides a facile pathway for synthesizing high-quality 2D heterojunctions, but also demonstrates their significant potential for high-performance optoelectronics through the effective interplay material synthesis and device physics.