论文部分内容阅读
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。
The energy band structure and optical properties of the cubic phase Ca2P0.25Si0.75 under (100) strain were simulated by the first-principles pseudopotential plane wave method based on density functional theory (DFT). The calculated results show that the bandgap of the cubic phase Ca2P0.25Si0.75 decreases gradually with the increase of compressive strain in the range of 90% ~ 100% of the compressive strain. With the strain of 100% ~ 102% When the strain is greater than 102%, the cubic phase Ca2P0.25Si0.75 transforms into an indirect bandgap semiconductor. In the strain range of 102% to 120%, the bandgap decreases as the strain increases. When the strain is applied, the optical properties of the cubic phase Ca2P0.25Si0.75 change significantly. When the compressive strain is increased, the dielectric constant of the Ca2P0.25Si0.75 cubic phase increases gradually with the increase of the refractive index and the absorption coefficient. When the strain increases, the reflectivity increases. Therefore, adopting the band structure and optical constants of the (100) strain-adjustable cubic phase Ca2P0.25Si0.75 is a means to effectively adjust the optoelectronic transmission performance.