掺杂Si/SiO_2界面电子结构与光学性质的第一性原理研究  

First-principles study on the electronic structure and optical properties of doped Si/SiO_2 interface

作　　者：顾芳 孙亚飞 张加宏[2] 何鹏翔 王丽阳 GU Fang;SUN Ya-Fei;ZHANG Jia-Hong;HE Peng-Xiang;WANG Li-Yang(School of Physics and Optoelectronic Engineering,Nanjing University of Information Science&Technology,Nanjing 210044,China;Jiangsu Key Laboratory of Meteorological Observation and Signal Processing, Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学物理与光电工程学院,南京210044 [2]南京信息工程大学江苏省气象探测与信息处理重点实验室,南京210044

出　　处：《原子与分子物理学报》2018年第5期853-860,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(61307113;61306138);江苏高校品牌专业建设工程项目(TAPP);江苏省高等学校大学生实践创新训练计划项目(201710300092)

摘　　要：采用基于密度泛函理论的第一性原理方法,在局域密度近似(LDA)下研究了B掺杂Si/SiO_2界面及其在压强作用下的电子结构和光学性质.能带的计算结果表明:掺杂前后Si/SiO_2界面均属于直隙半导体材料,但掺B后界面带隙由0. 74 eV减小为0. 57 eV,说明掺B使材料的金属性增强;对B掺杂Si/SiO_2界面施加正压强,发现随着压强不断增大,Si/SiO_2界面的带隙呈现了逐渐减小的趋势,并且由直隙逐渐转变为间隙.光学性质的计算结果表明:掺B对Si/SiO_2界面在低能区(即红外区)的介电函数虚部、吸收系数、折射率以及反射率等光学参数有显著影响,且在红外区出现新的吸收峰;对B掺杂Si/SiO_2界面施加正压强,随着压强增大,红外区的吸收峰逐渐消失,而在紫外区出现了吸收峰.上述结果表明,对Si/SiO_2界面掺B及施加正压强均可调控Si/SiO_2界面的电子结构与光学性质.本文的研究为基于Si/SiO_2界面的光电器件研究与设计提供一定的理论参考.The effects of B doping and high pressure on the electronic structure and optical properties of Si/SiO 2 interface are investigated by first-principles calculations based on density functional theory with the localized density approximation(LDA).The calculation results of the band structure show that the Si/SiO 2 interfaces before and after doping are all direct bandgap semiconducting materials,but the bandgap decreases from 0.74 eV to 0.57 eV after B doping,which indicates that the metal properties of Si/SiO 2 interfaces are enhanced.When the positive pressure is imposed on the Si/SiO 2 interface doped with B,it is found that the bandgap of the Si/SiO 2 interface decreases gradually with the increase of pressure,and gradually changes from the direct bandgap to the indirect bandgap.The calculation results of optical properties show that the influences of B doping on the optical parameters such as imaginary part of dielectric function,absorption coefficient,refractive index and reflectivity of Si/SiO 2 interface in the low energy region(ie,infrared region)are significant,and it appears obvious absorption peak in the infrared region.When imposing pressure on the Si/SiO 2 interface doped with B,the absorption peak in the infrared gradually disappears,and a small absorption peak appears in the ultraviolet region.The above results show that doping and pressure can effectively regulate the electronic and optical properties of the Si/SiO 2 interface.Our study provides some theoretical references for the research and design of Si/SiO 2 interface-based optoelectronic devices.

关 键 词：Si/SiO2界面 第一性原理 电子结构 光学性质 掺杂 压强 

分 类 号：O471[理学—半导体物理]