High-performance SnSe/Si heterojunction for self-powered vis-NIR photodetection and imaging.

The construction of heterojunction photodetectors represents a promising strategy for developing next-generation photodetection technologies. However, there are still significant challenges to overcome, such as low sensitivity, slow response times, and poor atmospheric stability, which severely limit their potential applications. In this study, high-quality SnSe films were deposited on a silicon substrate using magnetron sputtering technology, forming heterojunctions that enable self-powered photovoltaic broadband photodetection across the visible (VIS) to near-infrared (NIR) spectral range. The fabricated SnSe/Si heterojunction exhibits a low dark current and a broad spectral response from 405 to 980 nm. The detector demonstrates a microsecond-level response time under zero-bias and 405 nm illumination. It is also worthy of note that the device maintains excellent responsivity (R) and detectivity (D*) values of 262 mA W-1 and 6.98 × 1011 Jones, respectively, under 980 nm illumination. This work offers effective strategies for extending the capabilities of silicon-based photodetectors into the near-infrared spectrum and for fabricating low-cost, high-performance photodetectors.