(100)应变对立方相Ca_2P_(0.25)Si_(0.75)光电特性的影响  

Effect of(100) Strain on the Optical and Electrical Properties of Cubic Ca_2P_(0.25)Si_(0.75)

作　　者：岑伟富 杨吟野[1] 范梦慧[1] 杨文帮[1] 姚娟[1] 

机构地区：[1]贵州民族大学理学院,贵阳550025

出　　处：《半导体技术》2014年第9期707-713,共7页Semiconductor Technology

基　　金：教育部科学技术研究重点资助项目(210200);贵州民族大学科研资助项目(201427)

摘　　要：采用基于密度泛函理论（DFT）的第一性原理赝势平面波方法对（100）应变下立方相Ca2P0.25Si0.75的能带结构及光学性质进行了模拟计算。计算结果表明：在90%~100%的压应变范围,立方相Ca2P0.25Si0.75的带隙随着压应变增加逐渐减小;在100%~102%张应变范围,带隙随着张应变增加逐渐增大,张应变为102%时,带隙达到最大,Eg=0.513 9 eV;当张应变大于102%,立方相Ca2P0.25Si0.75转化为间接带隙半导体。在102%~120%应变范围,带隙随着应变增大而减小。当施加应变后立方相Ca2P0.25Si0.75的光学性质发生显著变化：增加压应变,立方相Ca2P0.25Si0.75的介电常数、折射率及吸收系数逐渐增加;增加张应变,反射率增加。因此,采用（100）应变可调制立方相Ca2P0.25Si0.75的能带结构和光学常数,是一种有效调节其光电传输性能的手段。Energy band structure and optical properties of cubic Ca2P0. 25Si0. 75under（ 100） strain were calculated by the first-principle pseudo-potential method based on the density functional theory（ DFT）. The results show that the band gap of the cubic Ca2P0. 25Si0. 75 decreases with the increase of the compressive strain in the range of 90%- 100%; the band gap increases with the increase of the tensile strain in the range of 100%- 102%,and the direct band gap is maximum with Egof 0. 513 9 eV at the tensile strain of 102%; Ca2P0. 25Si0. 75 turns to indirect band gap semiconductor when the tensile strain is more than 102%,and the band gap decreases with the increase of the tensile strain in the range of102%- 120%. The optical properties of cubic Ca2P0. 25Si0. 75 change greatly. The dielectric constant,refractive index and absorption coefficient of the cubic Ca2P0. 25Si0. 75 increase with the increase of the compressive strain; the reflectivity increases with the increase of the tensile strain. In conclusion,the energy band structure and optical properties of cubic Ca2P0. 25Si0. 75 were changed by（ 100） strain,it is an effective method of adjusting the photoelectric transmission performance of cubic Ca2P0. 25Si0. 75.

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

分 类 号：TN304.2[电子电信—物理电子学]