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

Wang, Hongbin; Zhou, Cheng; Li, Peng; Yang, Lin; Ma, Jiangang; Akaike, Ryota; Miyake, Hideto; Xu, Haiyang et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

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 Ga<sub>2</sub>O<sub>3</sub> 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 Ga<sub>2</sub>O<sub>3</sub>/AlN/AlGaN:Si solar-blind photodetector achieves a high responsivity of 0.73 A W<sup>‒1</sup> 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.