Spatial separation effect on the energies of uncorrelated and correlated electron-hole pair in CdSe/ZnS and InAs/InP core/shell spherical quantum dots
Abstract
The control of charge carriers states in coated semiconductors quantum dots constitute a
challenge to achieve a new range of tunable optoelectronic devices. The purpose of this
work is to investigate the ground state energies and the behaviors of correlated and non
correlated pair of electron (e) and hole (h) in CdSe=ZnSe and InAs=InP type I core/shell
spherical quantum dots taking into account the discontinuities of the dielectric constants
and effective masses. Analytical study of the uncorrelated e and h states allows to evaluate
the critical values of the core size corresponding to the escape of the electron and hole
from the core to the shell material. Then, the confined e and h wave functions and their
fundamental energies are determined according to their localization in the core/shell
structure. Knowing that the electron-hole interaction i.e “excitonic effect” turns out to be
crucial for a comprehension of the optical spectra, we extend our concept to the investi-
gation of the electron-hole correlations by a variational method.