High-Performance Narrow-Band Self-Powered Solar-Blind Ultraviolet Photodetector Enabled by the Hf _0.5 Zr _0.5 O ₂ /(Sn _0.1 Ga _0.9 ) ₂ O ₃ Heterojunction

While ferroelectric-enhanced Ga 2 O 3 -based self-powered solar-blind ultraviolet photodetectors (SBUVPDs) can offer high-performance detection of 200–280 nm wavelength due to efficient carrier separation, their accuracy is often compromised by the narrow bandgap (<4 eV) of traditional ferroelectric materials, which makes them susceptible to interference from light signals beyond the SBUV region. To address this issue, we developed a narrow-band self-powered SBUVPD based on Hf 0.5 Zr 0.5 O 2 /(Sn 0.1 Ga 0.9 ) 2 O 3 heterojunction thin films. This device benefits from a strong ferroelectric depolarization field throughout the whole Hf 0.5 Zr 0.5 O 2 thin film, and a type-II band alignment at the interfaces of Hf 0.5 Zr 0.5 O 2 and (Sn 0.1 Ga 0.9 ) 2 O 3, yielding excellent photoresponse performances with a high responsivity of 25.10 mA/W, large detectivity of 4.63 × 10 11 Jones, and fast rise/decay time of 201/325 ms at 0 V bias. Crucially, the ultrawide bandgap (5.45 eV) of Hf 0.5 Zr 0.5 O 2 confines the cutoff wavelength to within 280 nm, ensuring high detection accuracy. The overall performances of this device outperform those of the most recently reported SBUVPDs utilizing Ga 2 O 3 materials, demonstrating that integrating ultrawide-bandgap ferroelectric layers is an effective strategy for creating high-property, narrow-band SBUVPDs.