• Chinese Optics Letters
  • Vol. 21, Issue 4, 041604 (2023)
Xiaoguang Pan1, Yongzheng Wang1, Hangxin Bai1, Caixia Ren1, Jiangbo Peng1, Fangli Jing1, Hailong Qiu1, Zuotao Lei2、*, Hongjun Liu1、**, Chunhui Yang2, Zhanggui Hu1, and Yicheng Wu1
Author Affiliations
  • 1Tianjin Key Laboratory of Functional Crystal Materials, Institute of Functional Crystals, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China
  • 2Harbin Institute of Technology, Harbin 150001, China
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    DOI: 10.3788/COL202321.041604 Cite this Article Set citation alerts
    Xiaoguang Pan, Yongzheng Wang, Hangxin Bai, Caixia Ren, Jiangbo Peng, Fangli Jing, Hailong Qiu, Zuotao Lei, Hongjun Liu, Chunhui Yang, Zhanggui Hu, Yicheng Wu. Atomic structures and carrier dynamics of defects in a ZnGeP2 crystal[J]. Chinese Optics Letters, 2023, 21(4): 041604 Copy Citation Text show less

    Abstract

    ZnGeP2 (ZGP) crystals have attracted tremendous attention for their applications as frequency conversion devices. Nevertheless, the existence of native point defects, including at the surface and in the bulk, lowers their laser-induced damage threshold by increasing their absorption and forming starting points of the damage, limiting their applications. Here, native point defects in a ZGP crystal are fully studied by the combination of high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and optical measurements. The atomic structures of the native point defects of the Zn vacancy, P vacancy, and Ge-Zn antisite were directly obtained through an HAADF-STEM, and proved by photoluminescence (PL) spectra at 77 K. The carrier dynamics of these defects are further studied by ultrafast pump-probe spectroscopy, and the decay lifetimes of 180.49, 346.73, and 322.82 ps are attributed to the donor Vp+ → valence band maximum (VBM) recombination, donor GeZn+ → VBM recombination, and donor–acceptor pair recombination of Vp+ → VZn-, respectively, which further confirms the assignment of the electron transitions. The diagrams for the energy bands and excited electron dynamics are established based on these ultrahigh spatial and temporal results. Our work is helpful for understanding the interaction mechanism between a ZGP crystal and ultrafast laser, doing good to the ZGP crystal growth and device fabrication.
    Eg(T)=E0αT2/(T+β),

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    Xiaoguang Pan, Yongzheng Wang, Hangxin Bai, Caixia Ren, Jiangbo Peng, Fangli Jing, Hailong Qiu, Zuotao Lei, Hongjun Liu, Chunhui Yang, Zhanggui Hu, Yicheng Wu. Atomic structures and carrier dynamics of defects in a ZnGeP2 crystal[J]. Chinese Optics Letters, 2023, 21(4): 041604
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