Two-dimensional vertical-lateral hybrid heterostructure for ultrasensitive photodetection and image sensing

Constructing heterostructures of two-dimensional (2D) materials is critical for boosting their photoelectric performances, enabling a promising route to meet the harsh requirement of next-generation optoelectronic devices. However, the practical application of currently-studied lateral and vertical heterostructures is usually limited by poor photocarrier generation and transport abilities, primarily due to their inherent imbalance of depletion region and interface area. To solve this obstacle, we herein report a novel 2D hybrid heterostructure of bismuth selenide/oxyselenide with the coexistence of lateral and vertical interfaces. The unique hybrid structure provides the heterostructure with a huge interface area and a wide depletion region for sufficient photocarrier generation and separation, significantly improving the overall optoelectronic performances of the device. Specifically, the resultant photodetectors exhibit a remarkably decreased dark current and ultrafast photoresponse rate (τrise = 50 μs and τdecay = 20 μs). Moreover, our photodetector demonstrates outstanding image sensing capability for recording various complex patterns with high resolution over a wide spectral range from ultraviolet, visible to near-infrared regions. Our research provides a highly promising route for designing and fabricating novel geometries of 2D heterostructures to realize diverse photoelectric applications.