The different current–voltage (I–V) behaviors and leakage current mechanisms of AlGaN solar-blind ultraviolet avalanche photodiodes (APDs) have been investigated to better understand the relationships between multiplication gain and threading dislocations (TDs) in wide band gap AlGaN materials. The cross-sectional transmission electron microscopy (TEM) and first-principles calculations were used to study the types, location, density, and electronic structures of threading dislocations. The I–V behaviors of APDs for different types of dislocations were simulated based on the nonlocal band-to-band tunneling model; we found that 4-core-edge TDs in the avalanche region can give rise to electron tunneling from the valence band of p-AlGaN to the conduction band of i-AlGaN and results in a premature breakdown, and the multiplication gain were significantly reduced under high electric field. The dark current of avalanche devices with high gain were dominated by open core and full core screw TDs.

中文翻译：

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AlGaN太阳盲紫外雪崩光电二极管中不同的I – V行为和漏电流机理

不同的电流-电压（我- V）的AlGaN太阳能盲的行为和泄漏电流的机制紫外线雪崩光电二极管（APD）已被研究，以更好地理解乘法增益和宽的带隙的AlGaN材料穿透位错（TDS）之间的关系。截面透射电子显微镜（TEM）和第一性原理计算用于研究螺纹位错的类型，位置，密度和电子结构。在我- V基于非局部能带隧穿模型，模拟了APD在不同类型位错中的行为。我们发现雪崩区域中的4核边缘TD可以引起电子从p-AlGaN的价带到i-AlGaN的导带的隧穿并导致过早击穿，并且在高电场。高增益雪崩器件的暗电流主要由开芯和全芯螺杆TD决定。