摘要
运用第一性原理LDA+U方法(考虑了交换关联项的Hubbard U修正的局域密度近似方法)研究了过渡族金属X (X=Fe, Co, Ni)掺杂GaSb的电子结构和光学性质.研究结果表明:X掺杂均能提升GaSb半导体材料对红外光区光子的吸收幅度,并能有效提高GaSb材料的光催化性能;过渡金属X在GaSb材料中主要以X替代Ga缺陷(X@Ga)的形式存在, X的电荷布居和键布居表明, X的掺入容易引起体系的晶格畸变,由此产生的电偶极矩有利于光生电子-空穴对的分离,从而提高材料的光催化性能;X掺杂引入的杂质能级位于0点费米能级附近,因而掺杂体系复介电函数虚部在光子能量为0时就会有响应,同时掺杂体系的静介电常数也得到了很大的提升;X的掺杂对GaSb体系的光学性能都有很大的改善,但Ni掺入对改善GaSb材料的光催化特性最有利;最佳Ni原子的掺杂摩尔浓度为10.94%,均匀掺杂可以避免光生电子-空穴复合中心的形成,此时光学吸收范围和吸收峰值都达到最大,对材料的光催化性能最有利.
The electronic structures and optical properties of transition metal (TM, TM refers to Fe, Co, and Ni, respectively) doped GaSb are studied by the LDA+U method of the first-principles calculation. The results indicate that these TMs can enhance the absorption amplitudes of GaSb semiconductors in the infrared region, and improve the photocatalytic performances of GaSbs effectively. For the doped systems, TMs tend to substitute for Ga and form TM@Ga defect. The charge layout and bond population of TMs imply that the electric dipole moment induced by lattice distortion separates photoelectrons from holes to some degree, and consequently enhancing the photocatalytic performance. The impurity levels induced by TMs are close to the Fermi level, which illustrates that the imaginary part of complex dielectric function has the capability of response when the energy of photon is zero. Meanwhile, the static dielectric constant of the doped system is also enhanced compared with that of the un-doped system. The doped TMs can improve the optical properties of GaSb systems for three dopants effectively, but the Ni dopant is the best for the photocatalysis properties of GaSb in the three dopants. The further analysis shows that the uniform Ni can hinder the recombination of electron-hole pairs, and the optical absorption range and absorption peak are both biggest when Ni molar concentration is 10.94%, which is favorable for photocatalytic performance. Our results will extend the applications of GaSb to the fields of infrared thermal photovoltaic cells, infrared light detector, and infrared semiconductor laser.
作者
潘凤春
林雪玲
曹志杰
李小伏
Pan Feng-Chun;Lin Xue-Ling;Cao Zhi-Jie;Li Xiao-Fu(School of Physics and Electronic-Electrical Engineering, Ningxia University, Yinchuan 750021, China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第18期135-143,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11764032,51801107)
宁夏大学自然科学基金(批准号:ZR18008)
西部一流大学重大创新项目(批准号:ZKZD2017006)资助的课题~~
关键词
第一性原理
GASB
电子结构
光学性质
first-principles
GaSb
electronic structures
optical properties
