Self-polarization effects in spherical inverted core–shell quantum dot

Abstract

Single electron in spherical shell in infinite potential barrier is investigated. Schrödinger equation in effective mass approximation for this spherical heterosystem is solved to get eigenenergies and corresponding wave functions. In case of infinite potential barrier the ground state energy depends only on the shell width. Self-polarization potential is obtained by solving Poisson equation in three concentric spherical regions: core, shell and surrounding medium. Shell self-polarization energy depends on geometry (core and shell radius) and the dielectric mismatch at the quantum dot boundaries. Self-polarization energy is used as perturbation. One electron ground state energy results are presented in this paper. CdSe is placed in the shell. Surrounding medium is dielectric of smaller permittivity (vacuum or water), that is the most realistic case. The core dielectric permittivity influence on ground state energy is analysed. The self-polarization corrections to the ground state energy for different compositions, i.e. core and shell radius, are presented. For smaller core radius and the same shell thickness (which imply the same unperturbed ground state energy) bigger is the energy correction, i.e. perturbed energy state, for fixed value of the core dielectric permittivity. Increase of core dielectric permittivity produces decrease of energy correction.