Investigating the electronic structure and electric dipole polarizability of negative donor <i>D</i> ⁻ in direct or inverted spherical core/shell quantum dots (CSQDs)

Abstract

Abstract This work presents a theoretical study of energy levels, binding energies, and dipole polarizabilities of a negatively charged donor ( D − ) in CdSe / ZnTe and ZnTe / CdSe core/shell spherical quantum dots (CSQDs) embedded in silica. Calculations are performed within the framework of effective mass approximation using a configuration interaction method with B-spline basis functions. The dielectric constant, effective mass, and confinement potential are modeled using a Woods-Saxon shape to reflect realistic material interfaces. For CdSe / ZnTe CSQDs, both the binding energy and static dipole polarizability (SDP) show non-monotonic behavior as the core-to-shell ratio ( R c / R s ) increases, indicating a transition in impurity localization. In ZnTe / CdSe , the trend is reversed. The dynamic dipole polarizability (DDP) reveals resonance peaks whose redshift with size suggests strong tunability of the optical response. The results highlight the sensitivity of electronic and optical properties to the geometrical and material parameters of the CSQD, offering insights for the design of tunable optoelectronic devices.