Polaronic effect on linear and nonlinear optical properties of spherical quantum dots under electric field

• Polaronic effect or electric field redshifts the peak positions of ACs and RICs.
• Nonlinear ACs can not be ignored for the strong confinement potential.
• Polaronic effect is enhanced with the decreasing dot radius or Zn concentration.
• Electron-SO phonon interaction for the ground state depends on the electric field.
• Electron-CO (SO) phonon interaction is weakened (enhanced) by the electric field.

The polaronic effect on the linear and nonlinear optical properties of spherical quantum dots with a shallow hydrogenic impurity under electric field are studied, taking into account the interactions with both confined and surface optical phonons. In addition, the interaction between impurity and phonons has also been considered. Numerical results on typical Zn1−xCdxSe/ZnSe material show that the polaronic effect or electric field redshifts the peak positions of linear and nonlinear optical absorption coefficients and refractive index changes, but does not significantly affect the peak values of them. The polaronic effect is enhanced with the decreasing quantum dot radius or Zn concentrations. Additionally, it is found that the electric field has an important influence on the polaronic effect especially on the surface optical phonons.