High Responsivity, Low Dark Current Ultraviolet Photodetectors Based on Two-Dimensional Electron Gas Interdigitated Transducers
High Responsivity, Low Dark Current Ultraviolet Photodetectors Based on Two-Dimensional Electron Gas Interdigitated Transducers
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DOI：
10.1021/acsphotonics.8b01169
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发表时间：
2018-11-01
期刊：
影响因子：
7
通讯作者：
Senesky, Debbie G.
中科院分区：
文献类型：
--
作者：
Satterthwaite, Peter F.;Yalamarthy, Ananth Saran;Senesky, Debbie G.
采用AlGaN/GaN界面处形成的二维电子气（2DEG）作为叉指换能器（IDT）的紫外（UV）光电探测器在光激励下表征。2DEG-IDT光电探测器表现出创纪录的高归一化光电流暗电流比为6 × 10（14）。我们还观察到高响应度（7800 A/W）和紫外-可见光抑制比（10（6）），在任何GaN光电探测器架构的最高报告值。我们认为，在AlGaN/GaN异质结构的价带偏移是必不可少的，在实现这种高响应度，允许大的增益，而不需要存在的陷阱状态。我们提出的增益机制是一致的，与器件的沟道宽度和入射功率的增益缩放的测量。光电探测器架构具有简单的两步制造工艺，与AlGaN/GaN高电子迁移率晶体管（HEMT）工艺兼容。这种低暗电流、高响应度和简单制造的独特组合对于各种UV感测应用是有吸引力的。
An ultraviolet (UV) photodetector employing the two-dimensional electron gas (2DEG) formed at the AlGaN/GaN interface as an interdigitated transducer (IDT) is characterized under optical stimulus. The 2DEG-IDT photodetector exhibits a record high normalized photocurrent-to-dark current ratio of 6 x 10(14). We also observe a high responsivity (7800 A/W) and ultraviolet-visible rejection ratio (10(6)), among the highest reported values for any GaN photodetector architecture. We argue that the valence band offset in the AlGaN/GaN heterostructure is essential in achieving this high responsivity, allowing for large gains without necessitating the presence of trap states. Our proposed gain mechanism is consistent with measurements of the scaling of gain with device channel width and incident power. The photodetector architecture has a simple two-step fabrication process, compatible with AlGaN/GaN high electron mobility transistor (HEMT) processing. This unique combination of low dark current, high responsivity, and simple fabrication is attractive for a variety of UV sensing applications.