Inspecting the Role of Dimensional Anisotropy and Oxidized Environment on the Complex Dielectric Responses of CdSe/ZnS Ellipsoidal Core/Shell Quantum Dots with Embedded Impurities

Abstract

This research investigates the interplay between self-polarization, structural anisotropy and impurity effects on the complex dielectric function (CDF) of CdSe/ZnS ellipsoidal core–shell quantum dots (ECSQDs) surrounded by HfO₂ and SiO₂ oxides with the aim of optimizing their performance in next-generation optoelectronic devices. Analytical formulas of linear and third order nonlinear optical of susceptibility χ⁽³⁾ as well as the CDF are derived by compact-density matrix formalism applied to a two-state system. Numerical results indicated that electron energy states exhibited a complex dependence on both core and shell ellipticity (δ₁ and δ₂) along with witnessed red and blue shifts due to anisotropic quantum confinement along the major and minor axes. The oscillator strengths of quantum transitions non-monotonously depend on the structural anisotropy of the layers due to the different location of carriers. More importantly, computations showed that resonant peaks of real and imaginary parts of CDF could be precisely modulated through the dielectric medium, shape-induced effects and size parameters. The Eccentricity of the core seems to dominate over that of the shell affecting the amplitude of computed nonlinear properties. Our model can be engineered to optimize electron transport by enhancing energy confinement and protecting quantum information from destructive interference mechanisms.