摘要
Germanium diselenide(GeSe_(2))is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties.However,the evolution of lattice and electronic structure ofβ-GeSe_(2)at high pressure is still uncertain.Here we prepared high-qualityβ-GeSe_(2)single crystals by chemical vapor transfer(CVT)technique and performed systematic experimental studies on the evolution of lattice structure and bandgap ofβ-GeSe_(2)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 ofβ-GeSe_(2)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 ofβ-GeSe_(2)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 ofβ-GeSe_(2)and demonstrate the potential of pressure in modulating the material properties of two-dimensional(2D)Ge-based binary material.
作者
谢恒立
王家祥
王玲瑞
闫勇
郭娟
高其龙
晁明举
梁二军
任霄
Hengli Xie;Jiaxiang Wang;Lingrui Wang;Yong Yan;Juan Guo;Qilong Gao;Mingju Chao;Erjun Liang;Xiao Ren(Key Laboratory of Materials Physics of Ministry of Education,School of Physics and Microelectronics,Zhengzhou University,Zhengzhou 450052,China;College of Physics and Materials Science,Henan Normal University,Xinxiang 453007,China)
基金
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)
the Zhongyuan Academician Foundation(Grant No.ZYQR201810163)。