Temperature dependence and mechanism of PdSe2/Al2O3/AlGaN van der Waals heterostructure self-powered solar-blind photodetectors

Abstract

Despite the critical importance of operational stability and thermal reliability in practical photodetection systems, the temperature dependence and mechanism of two-dimensional (2D) material/AlGaN van der Waals (vdW) heterostructure self-powered solar-blind photodetectors (SBPDs) have been rarely studied owing to the inherent instability of traditional 2D materials. Herein, a stable and high-performance PdSe₂/Al₂O₃/AlGaN vdW heterostructure self-powered SBPD is presented, which exhibits remarkable temperature resilience from room temperature to 473 K. Systematic characterization revealed photocurrent peaks at 373 K (rise/fall time of 2/6 ms, responsivity of 188.8 mA W⁻¹ and detectivity of 8.9 × 10¹¹ Jones at 0 V) with 95.5% responsivity retention at 473 K. Additionally, the underlying physical mechanism of the varying photocurrent is explained by the competition of the generation of excess carriers and recombination rates at different temperatures. This study establishes fundamental guidelines for designing thermally robust self-powered SBPDs based on 2D material/AlGaN vdW heterostructures for commercial applications.