中国物理B ›› 2022, Vol. 31 ›› Issue (7): 76101-076101.doi: 10.1088/1674-1056/ac6db8

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Structural evolution and bandgap modulation of layered β-GeSe2 single crystal under high pressure

Hengli Xie(谢恒立)1, Jiaxiang Wang(王家祥)1, Lingrui Wang(王玲瑞)1, Yong Yan(闫勇)2, Juan Guo(郭娟)1, Qilong Gao(高其龙)1, Mingju Chao(晁明举)1, Erjun Liang(梁二军)1, and Xiao Ren(任霄)1,†   

  1. 1 Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China;
    2 College of Physics and Materials Science, Henan Normal University, Xinxiang 453007, China
  • 收稿日期:2022-03-28 修回日期:2022-05-03 接受日期:2022-05-07 出版日期:2022-06-09 发布日期:2022-06-21
  • 通讯作者: Xiao Ren E-mail:rxphy@zzu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12004339, 11874328, 11904322, 61804047, 22071221, and 21905252), China Postdoctoral Science Foundation (Grant Nos. 2018M640679 and 2019T120629), and the Zhongyuan Academician Foundation (Grant No. ZYQR201810163).

Structural evolution and bandgap modulation of layered β-GeSe2 single crystal under high pressure

Hengli Xie(谢恒立)1, Jiaxiang Wang(王家祥)1, Lingrui Wang(王玲瑞)1, Yong Yan(闫勇)2, Juan Guo(郭娟)1, Qilong Gao(高其龙)1, Mingju Chao(晁明举)1, Erjun Liang(梁二军)1, and Xiao Ren(任霄)1,†   

  1. 1 Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China;
    2 College of Physics and Materials Science, Henan Normal University, Xinxiang 453007, China
  • Received:2022-03-28 Revised:2022-05-03 Accepted:2022-05-07 Online:2022-06-09 Published:2022-06-21
  • Contact: Xiao Ren E-mail:rxphy@zzu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12004339, 11874328, 11904322, 61804047, 22071221, and 21905252), China Postdoctoral Science Foundation (Grant Nos. 2018M640679 and 2019T120629), and the Zhongyuan Academician Foundation (Grant No. ZYQR201810163).

摘要: Germanium diselenide (GeSe2) is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties. However, the evolution of lattice and electronic structure of $β$-GeSe2 at high pressure is still uncertain. Here we prepared high-quality $β$-GeSe2 single crystals by chemical vapor transfer (CVT) technique and performed systematic experimental studies on the evolution of lattice structure and bandgap of $β$-GeSe2 under pressure. High-precision high-pressure ultra low frequency (ULF) Raman scattering and synchrotron angle-dispersive x-ray diffraction (ADXRD) measurements support that no structural phase transition exists under high pressure up to 13.80 GPa, but the structure of $β$-GeSe2 turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa. Two Raman modes keep softening abnormally upon pressure. The bandgap of $β$-GeSe2 reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%, and the sample under pressure performs the piezochromism phenomenon. The bandgap after decompression is smaller than that in the atmospheric pressure environment, which is caused by incomplete recrystallization. These results enrich the insight into the structural and optical properties of $β$-GeSe2 and demonstrate the potential of pressure in modulating the material properties of two-dimensional (2D) Ge-based binary material.

关键词: high pressure, structural phase transition, Raman spectroscopy scattering, layered material

Abstract: Germanium diselenide (GeSe2) is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties. However, the evolution of lattice and electronic structure of $β$-GeSe2 at high pressure is still uncertain. Here we prepared high-quality $β$-GeSe2 single crystals by chemical vapor transfer (CVT) technique and performed systematic experimental studies on the evolution of lattice structure and bandgap of $β$-GeSe2 under pressure. High-precision high-pressure ultra low frequency (ULF) Raman scattering and synchrotron angle-dispersive x-ray diffraction (ADXRD) measurements support that no structural phase transition exists under high pressure up to 13.80 GPa, but the structure of $β$-GeSe2 turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa. Two Raman modes keep softening abnormally upon pressure. The bandgap of $β$-GeSe2 reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%, and the sample under pressure performs the piezochromism phenomenon. The bandgap after decompression is smaller than that in the atmospheric pressure environment, which is caused by incomplete recrystallization. These results enrich the insight into the structural and optical properties of $β$-GeSe2 and demonstrate the potential of pressure in modulating the material properties of two-dimensional (2D) Ge-based binary material.

Key words: high pressure, structural phase transition, Raman spectroscopy scattering, layered material

中图分类号:  (Crystallographic aspects of phase transformations; pressure effects)

  • 61.50.Ks
07.35.+k (High-pressure apparatus; shock tubes; diamond anvil cells) 78.30.-j (Infrared and Raman spectra) 63.22.Np (Layered systems)