(110)应变对立方相Ca_2P_(0.25)Si_(0.75)能带结构及光学性质的影响  

The effect of strain at the( 110) surface on the energy band structure and optical properties of cubic Ca_2P_(0. 25)Si_(0. 75)

作　　者：岑伟富 杨吟野[1] 范梦慧[1] 姚娟[1] 杨文帮[1] 黄金保[1] 

机构地区：[1]贵州民族大学理学院,贵阳550025

出　　处：《原子与分子物理学报》2015年第6期1038-1043,共6页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(51266002);教育部科学技术研究重点项目(210200);贵州省科学技术联合基金项目(LKM201130);贵州省优秀科技教育人才省长专项资金项目(201174)

摘　　要：采用第一性原理贋势平面波方法对（110）应变下立方相Ca_2P_（0.25）Si_（0.75）的能带结构及光学性质进行模拟计算,全面分析了应变对Ca_2P_（0.25）Si_（0.75）能带结构、光学性质的影响.计算结果表明：在92%～100%压应变范围内随着应变的逐渐增大导带向低能方向移动,价带向高能方向移动,带隙呈线性逐渐减小,但始终为直接带隙;在100%～102%张应变范围内随着应变的增加,带隙呈逐渐增大,应变达到102%直接带隙最大Eg=0.54378 e V;在102%～104%应变范围内随着应变的增加,带隙逐渐减小;当应变大于104%带隙变为间接带隙且带隙随着应变增大而减小.施加应变Ca_2P_（0.25）Si_（0.75）的介电常数、折射率均增大;施加压应变吸收系数增加,反射率减小;施加张应变吸收系数减小,反射率增加.综上所述,应变可以改变Ca_2P_（0.25）Si_（0.75）的电子结构和光学常数,是调节Ca_2P_（0.25）Si_（0.75）光电传输性能的有效手段.Energy band structure and optical properties of the cubic Ca_2P_（0.25）Si_（0.75） strained on the（ 110） surface have been calculated by the first- principle pseudo- potential method based on density functional theory（ DFT）. The results show that in the strain range 92% ～ 100%,Ca_2P_（0.25）Si_（0.75） is direct band gap semiconductor where the band gap decreases with the increase of strain,the conduction band moves to low- energy,while the valence band moves to high- energy. In the strain range 100% ～ 102% band gap increases with the increasing strained,and in the strained of 102%,the direct band gap is maximum Eg= 0. 5437 e V. In the strain range102% ～ 104% the band gap decreases with the increase of strained,and in the strain of 104% Ca_2P_（0.25）Si_（0.75） turn to indirect band gap semiconductor where the band gap decreases with the increasing of strain. The dielectric constant and refractive index of cubic Ca_2P_（0.25）Si_（0.75） are increased by strained,the absorption increases and the reflectivity decreases by compressive strained,but the absorption decreases and the reflectivity increases by the tensile strained. In conclusion,the strain can transform the energy band structure and optical properties of the cubic of Ca_2P_（0.25）Si_（0.75）,so,it is an effective method of adjusting the photoelectric transmission performance of cubic Ca_2P_（0.25）Si_（0.75）.

关 键 词：应变 光学性质 能带结构 第一性原理 Ca2P0.25Si0.75 

分 类 号：O472.3[理学—半导体物理]