Optical properties of a hydrogenic impurity in a confined Zn1−xCdxSe/ZnSe spherical quantum dot

The effect of longitudinal optical phonon field on the ground state and low lying-excited state energies of a hydrogenic impurity in a Zn1−xCdxSe/ZnSe strained quantum dot is investigated for various Cd content using the Aldrich–Bajaj effective potential. We consider the strain effect considering the internal electric field induced by the spontaneous and piezoelectric polarizations. Calculations have been performed using Bessel function as an orthonormal basis for different confinement potentials of barrier height. Polaron induced photoionization cross section of the hydrogenic impurity in the quantum dot is investigated. We study the oscillator strengths, the linear and third-order nonlinear optical absorption coefficients as a function of incident photon energy for 1s–1p and 1p–1d transitions with and without the polaronic effect. It is observed that the potential taking into account the effects of phonon makes the binding energies more than the obtained results using a Coulomb potential screened by a static dielectric constant and the optical properties of hydrogenic impurity in a quantum dot are strongly affected by the confining potential and the radii. It is also observed that the magnitude of the absorption coefficients increases for the transitions between higher levels with the inclusion of phonon effect.

► The effect of polaron in a Zn1−xCdxSe/ZnSe strained quantum dot is investigated. ► We use the Aldrich–Bajaj potential as effective Coulomb potential. ► The strain effect includes the internal electric field induced by the spontaneous and piezoelectric polarizations. ► Polaron induced photoionization cross section of the hydrogenic impurity in the quantum dot is investigated.