The detection of ultraviolet B (UVB) and UVC radiation is of paramount importance, and has expanding applications in industrial, scientific, environmental and biomedical fields. In this work, high-Al-content β-(Al_0.4Ga_0.6)₂O₃/Al_0.32Ga_0.68N films prepared via a thermal oxidation process from AlGaN layers are employed to fabricate UVC/UVB dual-band photodetectors (PDs). The PDs achieve two responsivity peaks at ∼200 nm and 305 nm, and also exhibit tunable dual-band photodetection, which can operate in separate UVB-dominated, UVC/UVB broadband and UVC-dominated detection modes by modulating the bias voltage from 10 V to 25 V. In particular, the PDs exhibit a responsivity (R) of 0.35 A W⁻¹, detectivity of 2.46 × 10¹² Jones, UVC/UVA rejection ratio (R₂₀₀/R₃₆₅) of 70 and UVC/visible rejection ratio (R₂₀₀/R₅₀₀) of 106 with an external quantum efficiency of 219% under 200 nm light illumination at 25 V bias, demonstrating good comprehensive performance over the UVC band. The tunable dual-band detection capability can be ascribed to the effect of increasing bias voltage on lowering the barrier height between electrodes and the (Al_xGa_1−x)₂O₃ layer, promoting the photogenerated electrons in (Al_xGa_1−x)₂O₃ films to easily cross over the reduced barrier height and contributing to the UVC detection. In addition to providing a facile, economical and feasible way to fabricate UVC/UVB tunable dual-band PDs via bias voltage regulation, this work is also expected to inspire further exploration on developing versatile and high-performance multi-band PDs.

中文翻译：

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基于 (Al0.4Ga0.6)2O3/Al0.32Ga0.68N 的高性能 UVC/UVB 可调谐双波段光电探测器

紫外线 B (UVB) 和 UVC 辐射的检测至关重要，并且在工业、科学、环境和生物医学领域有着广泛的应用。在这项工作中，采用AlGaN层通过热氧化工艺制备的高Al含量β-(Al _0.4 Ga _0.6 ) ₂ O ₃ /Al _0.32 Ga _0.68 N薄膜用于制造UVC/UVB双波段光电探测器(PD) 。 PD 在~200 nm 和 305 nm 处实现两个响应度峰值，并且还具有可调谐双波段光电检测功能，通过从 10 V 起调制偏置电压，可以在单独的 UVB 主导、UVC/UVB 宽带和 UVC 主导检测模式下工作特别是，PD 的响应度 ( R ) 为 0.35 AW ^-1，探测灵敏度为 2.46 × 10 ¹² Jones，UVC/UVA 抑制比 ( R ₂₀₀ / R ₃₆₅ ) 为 70，UVC/可见光抑制比 ( R ₂₀₀ / R ₅₀₀ )为106，在200 nm光照、25 V偏压下，外量子效率为219%，在UVC波段表现出良好的综合性能。可调双波段检测能力可归因于增加偏压对降低电极和(Al _x Ga _{1− x} ) ₂ O _{3层之间的势垒高度的影响，促进(Al x} Ga ₁₋ )中的光生电子的产生_x ) ₂ O ₃薄膜可以轻松跨越降低的势垒高度并有助于 UVC 检测。除了提供一种简便、经济且可行的方法来通过偏置电压调节来制造 UVC/UVB 可调谐双波段 PD 之外，这项工作还有望激发对开发多功能、高性能多波段 PD 的进一步探索。