Role of surrounding dielectric matrices on the nonlinear properties of group II-VI core/shell dot in the presence of electric field

Abstract

The effects of geometrical parameters, relaxation time, impurity distance, incident optical intensity and electric strength on binding energy of an impurity situated in CdSe/ZnS CSQD embedded into three commonly used dielectric environments (SiO2, CFM and 2M2P) are reported in the present paper. By means of effective mass approximation, density matrix approach and variationnal technique, electronic states and corresponding wavefunctions are employed in order to investigate the impact of mentioned parameters on the real and imaginary parts of both third order (nonlinear) optical suscepetibility as well as the complex dielectric function. The results show the effect of impact of dielectric environment surrounded by the core/shell dot, the third order (nonlinear) coefficients of dot embedded with SiO2 is found to be largest, the peak amplitude of third order susceptibility is blue shifted with the enhancement of electric field, the peak value not only increases but also suffers red shift as the optical intensity is increased, the single peak is doubled as the optical intensity is enhanced and it is broadened and the reduction of peak values of real and imaginary parts of dielectric function is observed with the surrounding of dielectric matrices. The dielectric environment, external perturbation, optical intensity in addition to the geometrical confinement can improve the performance of the optical properties.