AlGaN/GaN抛物量子点的尺寸相关三阶非线性极化率研究

Size-dependent Third-order Nonlinear Susceptibility of Parabolic AlGaN/GaN Quantum Dots

在有效质量近似框架下,通过求解AlxGa1-xN/GaN自组织圆柱形量子点的薛定谔方程,计算了量子点中导带电子在两个正交方向:Z‖和Z⊥方向上产生的三阶非线性极化率.计算中,电子的运动受到自组织量子点的抛物型束缚势和内建压电场的影响.计算表明,量子点的三阶非线性极化率的数量级达到了10-14m2/V2.进一步在Z‖和Z⊥方向上,考察了三阶非线性极化率与两个方向上的抛物束缚势的频率ωp、ωz,量子点的高度L,半径R,Al的含量x之间的关系.

The electron states confined in wurtzite Alx.Ga1-xN /GaN strained quantum dots （QDs） have been investigated in effective-mass approximation by solving Schrodinger equation, in which parabolic confined potential and the strong built-in electric field effect due to the piezoelectricity and spontaneous polarization have been taken into account. The third-order nonlinear susceptibility of the QDs in various directions （both parallel to z direction and vertical to z direction） have been calculated,and the magnitude reaches 10-14 m^2/V2. The results of how the third-order nonlinear susceptibility depend on the parabolic frequencies ωp,ωz,the radius R of QDs, the height L of QDs and the Al composition x of QDs have been given.