Interfacial Engineering of In₂Se₃/h-BN/CsPb(Br/I)₃ Heterostructure Photodetector and Its Application in Automatic Obstacle Avoidance System

Driven by the rapid development of autonomous vehicles,ultrasensitivephotodetectors with high signal-to-noise ratio and ultraweak lightdetection capability are urgently needed. Due to its intriguing attributes,the emerging van der Waals material, indium selenide (In2Se3), has attracted extensive attention as an ultrasensitivephotoactive material. However, the lack of an effective photoconductivegain mechanism in individual In2Se3 inhibitsits further application. Herein, we propose a heterostructure photodetectorconsisting of an In2Se3 photoactive channel,a hexagonal boron nitride (h-BN) passivation layer, and a CsPb(Br/I)(3) quantum dot gain layer. This device manifests a signal-to-noiseratio of 2 x 10(6) with responsivity of 2994 A/W anddetectivity of 4.3 x 10(14) Jones. Especially, it enablesthe detection of weak light as low as 0.03 & mu;W/cm(2). These performance characteristics are ascribed to the interfacialengineering. In2Se3 and CsPb(Br/I)(3) with type-II band alignment promote the separation of photocarriers,while h-BN passivates the impurities on CsPb(Br/I)(3) andpromises a high-quality carrier transport interface. Furthermore,this device is successfully integrated into an automatic obstacleavoidance system, demonstrating promising application prospects inautonomous vehicles.