| Sc、Ce掺杂CrSi2的电子结构与光学性质的第一性原理 |
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| 引用本文： | 叶建峰,肖清泉,秦铭哲,谢泉.Sc、Ce掺杂CrSi2的电子结构与光学性质的第一性原理[J].人工晶体学报,2021,50(8):1413-1421. |
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| 作者姓名： | 叶建峰 肖清泉 秦铭哲 谢泉 |
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| 作者单位： | 贵州大学大数据与信息工程学院,新型光电子材料与技术研究所,贵阳 550025 |
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| 基金项目： | 贵州省留学回国人员科技活动择优资助项目([2018]09);贵州省高层次创新型人才培养项目([2015]4015);贵州省研究生科研基金([2020]035) |
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| 摘 要： | 采用基于密度泛函理论的第一性原理赝势平面波方法对Sc、Ce单掺和共掺后CrSi2的几何结构、电子结构、复介电函数、吸收系数和光电导率进行了计算。结果表明:Sc、Ce掺杂CrSi2的晶格常数增大,带隙变小。本征CrSi2的带隙为0.386 eV,Sc、Ce单掺及共掺CrSi2的禁带宽度分别减小至0.245 eV、0.232 eV、0.198 eV,费米能级均向低能区移动进入价带。由于Sc的3d态电子和Ce的4f态电子的影响,Sc、Ce掺杂的CrSi2在导带下方出现了杂质能级。掺杂后的CrSi2介电函数虚部第一介电峰峰值增加且向低能方向移动,说明Sc、Ce掺杂使得CrSi2在低能区的光跃迁强度增强,Sc-Ce共掺时更明显。Sc、Ce掺杂的CrSi2吸收边在低能方向发生红移,在能量大于21.6 eV特别是在位于31.3 eV的较高能量附近,本征CrSi2几乎不吸收光子,Sc单掺和Sc-Ce共掺CrSi2吸收光子的能力有所增强,并在E=31.3 eV附近形成了第二吸收峰。说明掺杂Sc、Ce改善了CrSi2对红外和较高能区光子的吸收。在小于3.91 eV的低能区掺杂后的CrSi2光电导率增加。在20.01 eV<E<34.21 eV时,本征CrSi2光电导率为零,但Sc、Ce掺杂后的体系不为零,掺杂拓宽了CrSi2的光响应范围。研究结果为CrSi2基光电器件的应用与设计提供了理论依据。
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| 关 键 词： | 第一性原理 CrSi2 掺杂 电子结构 光学性质 |
| 收稿时间： | 2021-04-24 |
First-Principles Study on Electronic Structure and Optical Properties of Sc and Ce Doped CrSi2 |
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| YE Jianfeng,XIAO Qingquan,QIN Mingzhe,XIE Quan.First-Principles Study on Electronic Structure and Optical Properties of Sc and Ce Doped CrSi2[J].Journal of Synthetic Crystals,2021,50(8):1413-1421. |
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| Authors: | YE Jianfeng XIAO Qingquan QIN Mingzhe XIE Quan |
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| Affiliation: | Institute of Advanced Optoelectronic Materials and Technology, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China |
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| Abstract: | The first-principal pseudopotential plane wave method based on density functional theory was used to calculate the geometrical structure, electronic structure, complex dielectric function, absorption coefficient and photoconductivity of Sc or Ce doped and co-doped CrSi2, respectively. The results show that the lattice constants of CrSi2 increase with the doping of Sc and Ce, and the values of bandgap decrease with the co-doping of Sc and Ce. The band gaps of Sc, Ce and co-doped CrSi2 decrease to 0.245 eV, 0.232 eV and 0.198 eV, respectively. The Fermi level of doped CrSi2 moves to the low energy region and enters the valence band. Due to the major contribution of the 3d state electrons of Sc and 4f state electrons of Ce, the single Sc or Ce doped CrSi2 appears an impurity level below the conduction band. Sc-Ce co-doping makes CrSi2 transform into metal, and the electrical conductivity is improved obviously. After doping, the first dielectric peak of the imaginary part of the CrSi2 dielectric function increases and moves towards the direction of low energy, indicating that Sc or Ce doping enhances the optical transition intensity of CrSi2 in the low energy region, and great intensity is obtained when the CrSi2 is co-doped by Sc-Ce. The absorption edge of Sc or Ce doped CrSi2 redshifts in the low energy direction. The intrinsic CrSi2 hardly absorbs photons when the photon energy is greater than 21.6 eV, especially near higher photon energies at 31.3 eV. The absorption ability of Sc doped and Sc-Ce co-doped CrSi2 increases, and the second absorption peak is formed near E=31.3 eV. The results show that doping Sc or Ce can improve the absorption of CrSi2 to infrared and higher energy photons. The photoconductivity of CrSi2 increases after doping in the low energy region of less than 3.91 eV. In the energy range of 20.01 eV<E<34.21 eV, the photoconductivity of intrinsic CrSi2 is zero, but the photoconductivity of the Sc and Ce doped CrSi2 is not zero. Doping broadens the optical response range of CrSi2. The results provide a theoretical basis for the application and design of CrSi2-based optoelectronic devices. |
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| Keywords: | first-principle CrSi2 doping electronic structure optical property |
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