Role of Ga vacancies in enhancing the leakage current of GaN Schottky barrier ultraviolet photodetectors  

作　　者：赵德刚 张爽 刘文宝 郝小鹏 江德生 朱建军 刘宗顺 王辉 张书明 杨辉 魏龙 

机构地区：[1]State Key Laboratory on Integrated Optoelectronics,Institute of Semiconductors,Chinese Academy of Sciences [2]National Institute of Metrology [3]Institute of High Energy Physics,Chinese Academy of Sciences

出　　处：《Chinese Physics B》2010年第5期567-570,共4页中国物理B（英文版）

基　　金：Project supported by the National Science Fund for Distinguished Young Scholars (Grant No. 60925017);the National Natural Science Foundation of China (Grant Nos. 60836003 and 60776047);the National Basic Research Program of China (Grant No.2007CB936700);the National High Technology Research and Development Program of China (Grant No. 2007AA03Z401)

摘　　要：The leakage current of GaN Schottky barrier ultraviolet photodetectors is investigated. It is found that the photodetectors adopting undoped GaN instead of lightly Si-doped GaN as an active layer show a much lower leakage current even when they have a higher dislocation density. It is also found that the density of Ca vacancies in undoped GaN is much lower than in Si-doped GaN. The Ga vacancies may enhance tunneling and reduce effective Schottky barrier height, leading to an increase of leakage current. It suggests that when undoped GaN is used as the active layer, it is necessary to reduce the leakage current of GaN Schottky barrier ultraviolet photodetector.The leakage current of GaN Schottky barrier ultraviolet photodetectors is investigated. It is found that the photodetectors adopting undoped GaN instead of lightly Si-doped GaN as an active layer show a much lower leakage current even when they have a higher dislocation density. It is also found that the density of Ca vacancies in undoped GaN is much lower than in Si-doped GaN. The Ga vacancies may enhance tunneling and reduce effective Schottky barrier height, leading to an increase of leakage current. It suggests that when undoped GaN is used as the active layer, it is necessary to reduce the leakage current of GaN Schottky barrier ultraviolet photodetector.

关 键 词：Ga vacancies MOCVD GAN Schottky barrier photodetector 

分 类 号：TN36[电子电信—物理电子学]