中国物理B ›› 2021, Vol. 30 ›› Issue (12): 126104-126104.doi: 10.1088/1674-1056/ac2d1b

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Suppression of persistent photoconductivity in high gain Ga2O3 Schottky photodetectors

Haitao Zhou(周海涛), Lujia Cong(丛璐佳), Jiangang Ma(马剑钢), Bingsheng Li(李炳生), Haiyang Xu(徐海洋), and Yichun Liu(刘益春)   

  1. Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
  • 收稿日期:2021-07-07 修回日期:2021-08-25 接受日期:2021-10-06 出版日期:2021-11-15 发布日期:2021-11-25
  • 通讯作者: Jiangang Ma E-mail:majg@nenu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51872043, 51732003, and 51902049), the National Key R&D Program of China (Grant No. 2019YFA0705202), Natural Science Foundation of Jilin Province, China (Grant No. 20200201076JC), the National Basic Research Program of China (Grant No. 2012CB933703), and "111" Project (Grant No. B13013).

Suppression of persistent photoconductivity in high gain Ga2O3 Schottky photodetectors

Haitao Zhou(周海涛), Lujia Cong(丛璐佳), Jiangang Ma(马剑钢), Bingsheng Li(李炳生), Haiyang Xu(徐海洋), and Yichun Liu(刘益春)   

  1. Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
  • Received:2021-07-07 Revised:2021-08-25 Accepted:2021-10-06 Online:2021-11-15 Published:2021-11-25
  • Contact: Jiangang Ma E-mail:majg@nenu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51872043, 51732003, and 51902049), the National Key R&D Program of China (Grant No. 2019YFA0705202), Natural Science Foundation of Jilin Province, China (Grant No. 20200201076JC), the National Basic Research Program of China (Grant No. 2012CB933703), and "111" Project (Grant No. B13013).

摘要: The defect-related photoconductivity gain and persistent photoconductivity (PPC) observed in Ga2O3 Schottky photodetectors lead to a contradiction between high responsivity and fast recovery speed. In this work, a metal-semiconductor-metal (MSM) Schottky photodetector, a unidirectional Schottky photodetector, and a photoconductor were constructed on Ga2O3 films. The MSM Schottky devices have high gain (> 13) and high responsivity (> 2.5 A/W) at 230-250 nm, as well as slow recovery speed caused by PPC. Interestingly, applying a positive pulse voltage to the reverse-biased Ga2O3/Au Schottky junction can effectively suppress the PPC in the photodetector, while maintaining high gain. The mechanisms of gain and PPC do not strictly follow the interface trap trapping holes or the self-trapped holes models, which is attributed to the correlation with ionized oxygen vacancies in the Schottky junction. The positive pulse voltage modulates the width of the Schottky junction to help quickly neutralize electrons and ionized oxygen vacancies. The realization of suppression PPC functions and the establishment of physical models will facilitate the realization of high responsivity and fast response Schottky devices.

关键词: Ga2O3 Schottky photodetector, persistent photoconductivity, high gain, pulse voltage, oxygen vacancy

Abstract: The defect-related photoconductivity gain and persistent photoconductivity (PPC) observed in Ga2O3 Schottky photodetectors lead to a contradiction between high responsivity and fast recovery speed. In this work, a metal-semiconductor-metal (MSM) Schottky photodetector, a unidirectional Schottky photodetector, and a photoconductor were constructed on Ga2O3 films. The MSM Schottky devices have high gain (> 13) and high responsivity (> 2.5 A/W) at 230-250 nm, as well as slow recovery speed caused by PPC. Interestingly, applying a positive pulse voltage to the reverse-biased Ga2O3/Au Schottky junction can effectively suppress the PPC in the photodetector, while maintaining high gain. The mechanisms of gain and PPC do not strictly follow the interface trap trapping holes or the self-trapped holes models, which is attributed to the correlation with ionized oxygen vacancies in the Schottky junction. The positive pulse voltage modulates the width of the Schottky junction to help quickly neutralize electrons and ionized oxygen vacancies. The realization of suppression PPC functions and the establishment of physical models will facilitate the realization of high responsivity and fast response Schottky devices.

Key words: Ga2O3 Schottky photodetector, persistent photoconductivity, high gain, pulse voltage, oxygen vacancy

中图分类号:  (Vacancies)

  • 61.72.jd
73.30.+y (Surface double layers, Schottky barriers, and work functions) 85.60.Dw (Photodiodes; phototransistors; photoresistors) 85.30.De (Semiconductor-device characterization, design, and modeling)