中国物理B ›› 2021, Vol. 30 ›› Issue (11): 117302-117302.doi: 10.1088/1674-1056/abfa07
Yue-Bo Liu(柳月波)1, Jun-Yu Shen(沈俊宇)1, Jie-Ying Xing(邢洁莹)1, Wan-Qing Yao(姚婉青)1, Hong-Hui Liu(刘红辉)1, Ya-Qiong Dai(戴雅琼)1, Long-Kun Yang(杨隆坤)1, Feng-Ge Wang(王风格)1, Yuan Ren(任远)1, Min-Jie Zhang(张敏杰)1, Zhi-Sheng Wu(吴志盛)1,2, Yang Liu(刘扬)1,2, and Bai-Jun Zhang(张佰君)1,2,†
Yue-Bo Liu(柳月波)1, Jun-Yu Shen(沈俊宇)1, Jie-Ying Xing(邢洁莹)1, Wan-Qing Yao(姚婉青)1, Hong-Hui Liu(刘红辉)1, Ya-Qiong Dai(戴雅琼)1, Long-Kun Yang(杨隆坤)1, Feng-Ge Wang(王风格)1, Yuan Ren(任远)1, Min-Jie Zhang(张敏杰)1, Zhi-Sheng Wu(吴志盛)1,2, Yang Liu(刘扬)1,2, and Bai-Jun Zhang(张佰君)1,2,†
摘要: We report an abnormal phenomenon that the source-drain current (ID) of AlGaN/GaN heterostructure devices decreases under visible light irradiation. When the incident light wavelength is 390 nm, the photon energy is less than the band gaps of GaN and AlGaN whereas it can causes an increase of ID. Based on the UV light irradiation, a decrease of ID can still be observed when turning on the visible light. We speculate that this abnormal phenomenon is related to the surface barrier height, the unionized donor-like surface states below the surface Fermi level and the ionized donor-like surface states above the surface Fermi level. For visible light, its photon energy is less than the surface barrier height of the AlGaN layer. The electrons bound in the donor-like surface states below the Fermi level are excited and trapped by the ionized donor-like surface states between the Fermi level and the conduction band of AlGaN. The electrons trapped in ionized donor-like surface states show a long relaxation time, and the newly ionized donor-like surface states below the surface Fermi level are filled with electrons from the two-dimensional electron gas (2DEG) channel at AlGaN/GaN interface, which causes the decrease of ID. For the UV light, when its photon energy is larger than the surface barrier height of the AlGaN layer, electrons in the donor-like surface states below the Fermi level are excited to the conduction band and then drift into the 2DEG channel quickly, which cause the increase of ID.
中图分类号: (III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)