In this work, we demonstrate a high-performance ultraviolet phototransistor (UVPT) based on the AlGaN/GaN high-electron mobility transistor (HEMT) configuration. When the device is biased at off state, the peak photoresponsivity (R) of 3.6 × 10⁷ A/W under 265 nm illumination and 1.0 × 10⁶ A/W under 365 nm illumination can be obtained. Those two R values are one of the highest among the reported UVPTs at the same detection wavelength under off-state conditions. In addition, we investigate the gate-bias (V_GS) dependent photoresponse of the fabricated device with the assistance of band structure analysis. It was found that a more negative V_GS can significantly reduce the rise/decay time for 265 nm detection, especially under weak illumination. This can be attributed to a largely enhanced electric field in the absorptive AlGaN barrier that pushes the photo-generated carriers rapidly into the GaN channel. In contrast, the V_GS has little impact on the switching time for 365 nm photodetection, since the GaN channel has a larger absorption depth and the entire UVPT simply acts as a photoconductive-type device. In short, the proposed AlGaN/GaN HEMT structure with the superior photodetection performance paves the way for the development of next generation UVPTs.

中文翻译：

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展示具有超过 3.6 × 107A/W 的创纪录高响应度的基于 AlGaN/GaN 的紫外光电晶体管

在这项工作中，我们展示了一种基于 AlGaN/GaN 高电子迁移率晶体管 (HEMT) 配置的高性能紫外光电晶体管 (UVPT)。当器件在关闭状态下偏置时，在 265 nm 光照下可以获得3.6 × 10 ⁷ A/W的峰值光响应率 ( R )，在 365 nm 光照下可以获得1.0 × 10 ⁶ A/W。这两个R值是在关闭状态条件下相同检测波长下报告的 UVPT 中最高的值之一。此外，我们在能带结构分析的帮助下研究了所制造器件的栅极偏置 ( V _GS ) 相关光响应。发现更负的V _GS可以显着减少 265 nm 检测的上升/衰减时间，尤其是在弱光照下。这可归因于吸收性 AlGaN 势垒中大大增强的电场，该势垒将光生载流子迅速推入 GaN 通道。相比之下，V _GS对 365 nm 光电探测的切换时间影响很小，因为 GaN 通道具有更大的吸收深度，并且整个 UVPT 只是充当光电导型器件。总之，所提出的具有卓越光电探测性能的 AlGaN/GaN HEMT 结构为下一代 UVPT 的发展铺平了道路。