暗电流
光电子学
雪崩光电二极管
材料科学
响应度
电场
击穿电压
极化(电化学)
雪崩击穿
量子隧道
氮化镓
APDS
光电二极管
宽禁带半导体
光学
电压
物理
光电探测器
图层(电子)
化学
纳米技术
物理化学
探测器
量子力学
作者
Xiaodong Wang,Weida Hu,Xiaohong Chen,Jintong Xu,Ling Wang,Xiangyang Li,Wei Lü
标识
DOI:10.1088/0022-3727/44/40/405102
摘要
GaN/AlGaN avalanche photodiodes (APD) are fabricated based on GaN/AlGaN materials of epitaxial growth. Dark current and photoresponse characteristics are shown experimentally and theoretically. The effects of polarization charge density (PCD) on the dark current of GaN/AlGaN APDs are investigated in detail. It is demonstrated that an increased PCD reduces the electric field intensity in the GaN i-region, and results in an increase in breakdown voltage and a decrease in dark current above 65 V reverse bias. However, it is indicated that increasing the PCD elevates the electric field intensity at the GaN/AlGaN interface, and thus induces an enhancement of the band-to-band tunnelling and trap-assisted tunnelling processes, and eventually an evident rise in the dark current below 50 V reverse bias. Additionally, the effects of PCD on the optical responsivity are studied in detail. Results show that positive polarization charge has little effect on the photoresponse of the device. However, the negative polarization charge significantly affects the photoresponse. A metal–oxide–semiconductor inversion layer model has been proposed to explain the effect of negative polarization charge on photoresponse.
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