Tuning linear and nonlinear optical properties of wurtzite GaN by c-axial stress
Tuning linear and nonlinear optical properties of wurtzite GaN by c-axial stress
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DOI：
10.1088/0022-3727/42/18/185107
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发表时间：
2009-09-21
影响因子：
3.4
通讯作者：
Guo, Guang-Yu
中科院分区：
文献类型：
--
作者：
Cai, Duanjun;Guo, Guang-Yu
利用密度泛函理论计算方法研究了纤锌矿结构GaN在c轴应力场作用下的线性和非线性光学性质。在每个c轴应变下进行了完全的结构优化。计算的介电函数表明，拉伸c轴应变有效地提高了线性光学效率，特别是对于带-边跃迁，并显著增加了电子在导带内的迁移率。二阶非线性光学极化率表明，拉伸c轴应变将增强GaN的零频和低频非线性响应。其非线性光学性能的提高可以用纤锌矿GaN在c轴拉伸应变下的偏振降低来解释。基于这些发现，我们提出了一种通过在高对称性晶体方向施加适当的应力来改善晶体的电学和光学性质的方法。
We study the linear and nonlinear optical properties of wurtzite GaN under a c-axial stress field, using density functional theory calculations. The fully structural optimization at each c-axial strain was performed. The calculated dielectric functions show that tensile c-axial strain effectively improves the linear optical efficiency, especially for the band-edge transitions, and significantly increases the mobility of electrons in the conduction band. Second-order nonlinear optical susceptibilities show that the tensile c-axial strain will enhance the zero-and low-frequency nonlinear responses of GaN. The enhancement of the nonlinear optical property is explained by the reduction in the polarization of wurtzite GaN under tensile c-axial strains. Based on these findings, we propose a method for improving the electrical and optical properties of the crystal by imposing appropriate stress on the high symmetry crystalline directions.