nc-Si/SiO_2球形量子点的三阶极化率

Third-order Nonlinear Susceptibility in a nc-Si/SiO_2 Spherical Quantum Dot

在有效质量近似下,采用无限深势阱,理论计算nc-Si/SiO2球形量子点导带中的电子束缚态,并利用紧束缚密度矩阵理论,推导出共振三阶极化率的表达式.通过数值模拟,分析讨论nc-Si/SiO2球形量子点的三阶极化率与量子点半径、入射光子的能量和弛豫相的关系.结果表明,在强受限中,三阶极化率与量子点半径、入射光子能量和弛豫相有着显著的关系.随着量子点半径的增大、入射光子能量的增大和弛豫相的减小,三阶极化率都有不同程度的增强.

Under the effective mass approximation, the electron state is considered to be confined within a nc-Si/SiO2spherical quantum dot with infinite barrier, and by using the compact density matrix method, the analytic expression for the resonant third-order susceptibilities was derived. According to numerical simulation, the relation of the third-order susceptibilities with quantum dot dimension, incident photo energy and various relaxation rate was discussed. The result shows that the third-order susceptibilities strongly depends on quantum dot dimensions, incident photon energy and various relaxation rate. The third-order susceptibilities increases with an increase in quantum dot dimension and incident photo energy and a decrease in various relaxation rate.