High-sensitivity and fast-response solar-blind photodetectors via band offset engineering for motion tracking

Single-pixel imaging is emerging as a promising alternative to traditional focal plane array technologies, offering advantages in compactness and cost-effectiveness. However, the lack of solar-blind photodetectors combining fast-response and high-sensitivity has constrained their application in the deep ultraviolet spectrum. This work introduces a self-powered solar-blind photodetector based on a heterostructure comprising a Ga₂O₃ photosensitive layer, an AlN barrier layer, and an N-polar AlGaN:Si contact layer. The polarization field within the AlN layer induces band bending, creating potential wells that confine photogenerated holes and thereby generate photocurrent gain. Consequently, the Ga₂O₃/AlN/AlGaN:Si solar-blind photodetector achieves a high responsivity of 0.73 A W^‒1 and a rapid decay time of 56 µs. This performance enables 256 × 256 resolution solar-blind single-pixel imaging of both static fingerprints and moving objects. The proposed band offset engineering strategy opens a pathway for developing solar-blind photodetectors and solar-blind imaging technologies.