CAJ | 학술논문

采用第一性原理贋势平面波方法对(110)应变下立方相Ca2 P0．25 Si0．75的能带结构及光学性质进行模拟计算，全面分析了应变对Ca2 P0．25 Si0．75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 eV；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Ca2 P0．25 Si0．75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Ca2 P0．25 Si0．75的电子结构和光学常数，是调节Ca2 P0．25 Si0．75光电传输性能的有效手段．
채용제일성원리안세평면파방법대(110)응변하립방상Ca2 P0．25 Si0．75적능대결구급광학성질진행모의계산，전면분석료응변대Ca2 P0．25 Si0．75능대결구、광학성질적영향．계산결과표명：재92%~100%압응변범위내수착응변적축점증대도대향저능방향이동，개대향고능방향이동，대극정선성축점감소，단시종위직접대극；재100%~102%장응변범위내수착응변적증가，대극정축점증대，응변체도102%직접대극최대Eg=0．54378 eV；재102%~104%응변범위내수착응변적증가，대극축점감소；당응변대우104%대극변위간접대극차대극수착응변증대이감소．시가응변Ca2 P0．25 Si0．75적개전상수、절사솔균증대；시가압응변흡수계수증가，반사솔감소；시가장응변흡수계수감소，반사솔증가．종상소술，응변가이개변Ca2 P0．25 Si0．75적전자결구화광학상수，시조절Ca2 P0．25 Si0．75광전전수성능적유효수단．
Energy band structure and optical properties of the cubic Ca2 P0. 25 Si0. 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%, Ca2 P0. 25 Si0. 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 eV. In the strain range 102% ~104% the band gap decreases with the increase of strained, and in the strain of 104% Ca2 P0. 25 Si0. 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 Ca2 P0. 25 Si0. 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 Ca2 P0. 25 Si0. 75 , so, it is an effective method of adjusting the photoelectric transmission performance of cu-bic Ca2 P0. 25 Si0. 75.