Planar AI/GaN/Ni Schottky diodes were realized on GaN films deposited on sapphire substrates and characterized in the dark and under illumination. The optoelectronic characteristics of GaN photodetectors appear largely influenced by structural defects and impurities, which are clearly detected in photocurrent yield measurements. In particular, an exponential increase of the photocurrent is observed and explained in terms of a barrier lowering photoeffect, hence a light induced shrinking of the space charge region, related to carrier trapping at defects and impurities. Trapping events are also responsible for a dispersive behavior of the AC responsivity with the light chopping frequency. Such effects point out the importance of a proper selection of bias voltage and working frequency for GaN photodetector operations
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机译：平面AI / GaN / Ni肖特基二极管在沉积在蓝宝石底物上的GaN膜上实现，并在黑暗和照明中表征。 GaN光电探测器的光电特性似乎受到结构缺陷和杂质的影响，其在光电流产量测量中清楚地检测到。特别地，观察到光电流的指数增加，并根据屏障降低光额来解释，因此与缺陷和杂质的载体捕获有关的空间电荷区域的光引起的光诱导。捕获事件也负责与光斩波频率的AC响应度的分散行为。 Such effects point out the importance of a proper selection of bias voltage and working frequency for GaN photodetector operations
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