中国物理B ›› 2010, Vol. 19 ›› Issue (5): 57802-057802.doi: 10.1088/1674-1056/19/5/057802

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

魏龙1, 郝小鹏2, 赵德刚3, 张爽3, 刘文宝3, 江德生3, 朱建军3, 刘宗顺3, 王辉3, 张书明3, 杨辉3   

  1. (1)Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China; (2)National Institute of Metrology, Beijing 100013, China; (3)State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • 收稿日期:2009-09-14 修回日期:2009-11-30 出版日期:2010-05-15 发布日期:2010-05-15
  • 基金资助:
    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) and the National High Technology Research and Development Program of China (Grant No. 2007AA03Z401).

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

Zhao De-Gang(赵德刚)a)†, Zhang Shuang(张爽)a), Liu Wen-Bao(刘文宝)a), Hao Xiao-Peng(郝小鹏)b), Jiang De-Sheng(江德生) a), Zhu Jian-Jun(朱建军)a), Liu Zong-Shun(刘宗顺)a), Wang Hui(王辉) a), Zhang Shu-Ming(张书明)a), Yang Hui(杨辉)a), and Wei Long(魏龙)c)   

  1. a State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; b National Institute of Metrology, Beijing 100013, China; c Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China
  • Received:2009-09-14 Revised:2009-11-30 Online:2010-05-15 Published:2010-05-15
  • Supported by:
    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) and the National High Technology Research and Development Program of China (Grant No. 2007AA03Z401).

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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 Ga 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.

Abstract: 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 Ga 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.

Key words: Ga vacancies, MOCVD, GaN, Schottky barrier photodetector

中图分类号:  (Surface double layers, Schottky barriers, and work functions)

  • 73.30.+y
85.60.Gz (Photodetectors (including infrared and CCD detectors)) 61.72.J- (Point defects and defect clusters)