The AlGaN-based solar-blind ultraviolet (SBUV) detectors have tremendous potential applications in missile warning, secret communications, deep space exploration, etc. In this work, we have proposed a strategy to improve the response as well as the photo-to-dark current ratio (PDCR) of the AlGaN-based polarization-enhanced SBUV detector by inserting an AlN spacer between the high-Al barrier and the low-Al channel layer. On the one hand, the AlN spacer can enhance the polarization field and increase the effective conduction band offset, increasing the photogenerated electron–hole pairs’ separation efficiency and channel conduction ability. On the other hand, the AlN spacer can lift the effective barrier height of the channel electrons, suppressing the dark current. Moreover, the AlN spacer can reduce the alloy disorder scattering and Coulomb scattering of the channel electrons, enhancing electron mobility. Consequently, an extremely low dark current below 1 pA and a PDCR exceeding 10⁸ under an incident light power density of 5.4 μW/cm² at 250 nm are obtained at 5 V. The spectral response shows a peak responsivity of 1.2 × 10⁶ A/W, corresponding to a current gain of over 5 × 10⁶, which is near 3 orders of magnitude higher than that of the reference detector without an AlN spacer layer. The light power density-dependent response and response time measurements are also performed to investigate the gain enhancement mechanism. The detectors are employed into a scanning imaging system to obtain a SBUV image to confirm the superiority of introducing an AlN spacer layer into AlGaN-based polarization-enhanced detectors in real applications.

中文翻译：

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在基于 AlGaN 的偏振增强型日盲紫外探测器的势垒层和沟道层之间插入 AlN 间隔物

基于AlGaN的日盲紫外（SBUV）探测器在导弹预警、秘密通信、深空探测等方面具有巨大的应用潜力。在这项工作中，我们提出了一种提高响应和光电转换的策略。通过在高铝势垒层和低铝沟道层之间插入 AlN 间隔物，可以提高基于 AlGaN 的偏振增强 SBUV 探测器的暗电流比 (PDCR)。一方面，AlN间隔物可以增强极化场并增加有效导带偏移，提高光生电子空穴对的分离效率和沟道传导能力。另一方面，AlN侧墙可以提高沟道电子的有效势垒高度，抑制暗电流。此外，AlN间隔物可以减少沟道电子的合金无序散射和库仑散射，从而增强电子迁移率。因此，在5 V电压下，在250 nm处的入射光功率密度为5.4 μW/cm ²下，获得了低于1 pA的极低暗电流和超过10 ⁸的PDCR 。光谱响应显示出1.2 × 10 ⁶ A的峰值响应度/W，对应于超过 5 × 10 ⁶的电流增益，比没有 AlN 间隔层的参考探测器高出近 3 个数量级。还执行光功率密度相关的响应和响应时间测量来研究增益增强机制。将探测器应用于扫描成像系统以获得SBUV图像，以证实在实际应用中将AlN间隔层引入到AlGaN基偏振增强探测器中的优越性。