制备和表征了p-i-n型的GaN基雪崩探测器。器件在-5 V下的暗电流约为0.05 nA, -20 V下的暗电流小于 0.5 nA。响应增益-偏压曲线显示, 可重复的雪崩增益起始于80 V附近, 在85 V左右增益达到最大为120, 表明所制备的器件具有较好的质量。C-V测量用来确定载流子的分布和耗尽信息, 结果显示, p型层在15 V左右达到耗尽, 对应的空穴载流子浓度在1.9×1017 cm-1左右, 相对低的载流子浓度降低了电场限制, 使探测器的工作电压相对偏高。在不同偏压下测量的光谱响应曲线显示出明显的Franz-Keldysh效应。

p-i-n GaN based avalanche UV photodetectors were fabricated and characterized. Dark current of the device is as low as 0.05 nA at the reverse bias of 5 V and ＜0.5 nA at 20 V. Repeatable photocurrent avalanche gain, began at around 80 V and grew up to a peak of 120 at about 85 V, demonstrating a good material quality. C-V mea-surement was used to determine carrier distribution and depletion information, and it showed that p-layer fully depleted at reverse bias of about 15 V, resulting in a hole concentration of 1.9×1017 cm-3. The relative low hole concentration might lead to a weak confinement of electrical field and an increase in the operating voltage of the device. Photocurrent spectroscopy under various bias was also measured and exhibited obvious Franz-Keldysh effect.