椭球形反转核/壳量子点中杂质态的结合能及光致电离截面

Binding Energies of Impurity States and Photoionization Cross Sections in Ellipsoidal Inverted Core/Shell Quantum Dots

利用变分理论和有效质量近似,研究了核为势垒、壳为势阱的椭球形反转核/壳量子点中杂质态结合能及光致电离截面随体系尺寸、椭球率以及杂质位置的变化关系。数值计算结果表明:量子点尺寸和形状对结合能及光致电离截面有着重要的影响,且结合能随量子点尺寸和杂质位置变化呈非单调变化,当壳厚度较小时椭球率的影响明显,且随着椭球率的增大结合能增加;光致电离截面的峰值强度在不同杂质位置、不同椭球率下均随着核尺寸增加而增大,并伴随着峰值位置出现红移或蓝移现象。

Under the effective mass approximation,the impurity state binding energy and photoionization cross section in ellipsoidal inverted core/shell quantum dots with the core as potential barrier and the shell as potential well as functions of the system size,ellipticity,and position of the impurity have been studied.Numerical calculations show that the size and shape of the quantum dots have important effects on the binding energy and photoionization cross section.The binding energy and photoionization cross section vary non-monotonically with the quantum dot size,the influence of ellipticity is obvious when the shell thickness is small,and the binding energy increases with the increasing ellipticity.The peak intensity of the photoionization cross section increases with the increasing core size at different impurity positions and ellipticities,and the peak position appears the redshift or blueshift.