中国物理B ›› 2023, Vol. 32 ›› Issue (4): 48502-048502.doi: 10.1088/1674-1056/ac8ce9

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Thickness effect on solar-blind photoelectric properties of ultrathin β-Ga2O3 films prepared by atomic layer deposition

Shao-Qing Wang(王少青)1, Ni-Ni Cheng(程妮妮)1, Hai-An Wang(王海安)1, Yi-Fan Jia(贾一凡)1, Qin Lu(陆芹)1, Jing Ning(宁静)2, Yue Hao(郝跃)2, Xiang-Tai Liu(刘祥泰)1,†, and Hai-Feng Chen(陈海峰)1,‡   

  1. 1 The Key Laboratory of Advanced Semiconductor Devices and Materials, Xi'an University of Posts&Telecommunications, Xi'an 710121, China;
    2 The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi'an, 710071, China
  • 收稿日期:2022-07-15 修回日期:2022-08-24 接受日期:2022-08-26 出版日期:2023-03-10 发布日期:2023-04-04
  • 通讯作者: Xiang-Tai Liu, Hai-Feng Chen E-mail:liuxiangtai@xupt.edu.cn;chenhaifeng@xupt.edu.cn
  • 基金资助:
    Project supported by the Natural Science Basic Research Program of Shaanxi Province, China (Grant No. 2022JQ-701) and the Scientific Research Program Funded by Shaanxi Provincial Education Department, China (Grant No. 21JK0919).

Thickness effect on solar-blind photoelectric properties of ultrathin β-Ga2O3 films prepared by atomic layer deposition

Shao-Qing Wang(王少青)1, Ni-Ni Cheng(程妮妮)1, Hai-An Wang(王海安)1, Yi-Fan Jia(贾一凡)1, Qin Lu(陆芹)1, Jing Ning(宁静)2, Yue Hao(郝跃)2, Xiang-Tai Liu(刘祥泰)1,†, and Hai-Feng Chen(陈海峰)1,‡   

  1. 1 The Key Laboratory of Advanced Semiconductor Devices and Materials, Xi'an University of Posts&Telecommunications, Xi'an 710121, China;
    2 The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi'an, 710071, China
  • Received:2022-07-15 Revised:2022-08-24 Accepted:2022-08-26 Online:2023-03-10 Published:2023-04-04
  • Contact: Xiang-Tai Liu, Hai-Feng Chen E-mail:liuxiangtai@xupt.edu.cn;chenhaifeng@xupt.edu.cn
  • Supported by:
    Project supported by the Natural Science Basic Research Program of Shaanxi Province, China (Grant No. 2022JQ-701) and the Scientific Research Program Funded by Shaanxi Provincial Education Department, China (Grant No. 21JK0919).

摘要: The $\beta $-Ga$_{2}$O$_{3}$ films with different thicknesses are prepared by an atomic layer deposition system. The influence of film thickness on the crystal quality is obvious, indicating that the thicker films perform better crystal quality, which is verified from x-ray diffraction (XRD) and scanning electron microscope (SEM) results. The Ga$_{2}$O$_{3}$-based solar blind photodetectors with different thicknesses are fabricated and studied. The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness. The photodetectors with inter-fingered structure based on 900 growth cycles $\beta $-Ga$_{2}$O$_{3}$ active layers (corresponding film thickness of 58 nm) exhibit the best performances including a low dark current of 134 fA, photo-to-dark current ratio of 1.5$\times10^{7}$, photoresponsivity of 1.56 A/W, detectivity of 2.77$\times10^{14}$ Jones, and external quantum efficiency of 764.49% at a bias voltage of 10 V under 254-nm DUV illumination. The photoresponse rejection ratio ($R_{254}/R_{365}$) is up to $1.86\times 10^{5}$. In addition, we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure. As the finger spacing decreases from 50 μm to 10 μm, the photoresponsivity, detectivity, and external quantum efficiency increase significantly.

关键词: β-Ga2O3, film thickness, solar blind photodetectors, photoelectric response

Abstract: The $\beta $-Ga$_{2}$O$_{3}$ films with different thicknesses are prepared by an atomic layer deposition system. The influence of film thickness on the crystal quality is obvious, indicating that the thicker films perform better crystal quality, which is verified from x-ray diffraction (XRD) and scanning electron microscope (SEM) results. The Ga$_{2}$O$_{3}$-based solar blind photodetectors with different thicknesses are fabricated and studied. The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness. The photodetectors with inter-fingered structure based on 900 growth cycles $\beta $-Ga$_{2}$O$_{3}$ active layers (corresponding film thickness of 58 nm) exhibit the best performances including a low dark current of 134 fA, photo-to-dark current ratio of 1.5$\times10^{7}$, photoresponsivity of 1.56 A/W, detectivity of 2.77$\times10^{14}$ Jones, and external quantum efficiency of 764.49% at a bias voltage of 10 V under 254-nm DUV illumination. The photoresponse rejection ratio ($R_{254}/R_{365}$) is up to $1.86\times 10^{5}$. In addition, we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure. As the finger spacing decreases from 50 μm to 10 μm, the photoresponsivity, detectivity, and external quantum efficiency increase significantly.

Key words: β-Ga2O3, film thickness, solar blind photodetectors, photoelectric response

中图分类号:  (Photodetectors (including infrared and CCD detectors))

  • 85.60.Gz
81.15.Gh (Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)) 73.63.Bd (Nanocrystalline materials)