Energy spectrum of an exciton in a CdSe/ZnTe type-II core/shell spherical quantum dot. (January 2017)

• Record Type: Journal Article
• Authors: Chafai, A.; Dujardin, F.; Essaoudi, I.; Ainane, A.
• Is Part Of: Superlattices and microstructures. Volume 101(2017)
• Page Start: 40
• Page End: 48
• Publication Date: 2017-01
• Subjects: Exciton -- Core/shell nanostructure -- Type II quantum dot; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2016.11.017
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: The binding energy of an exciton inside a CdSe/ZnTe core/shell spherical quantum dot was theoretically examined taking into account the dependence of the dielectric constant and charge carriers effective mass on radius, and using the envelope function approximation. Such a structure presents original optical and electronic properties because of the spatial separation of electrons and holes caused by the type-II alignment of energy states. The mean distance between the electron and hole was calculated variationally using a trial function taking into account the coulomb interaction between charge carriers. Our numerical results provide a description to the size dependence of the binding energy of an exciton inside a core/shell nanoheterostructure type-II. Indeed, by controlling the inner and outer radii, we can precisely control the energy spectrum of the exciton. Highlights: Theoretical model of an exciton in a CdSe/CdTe type II core/shell nanodot. Determination of the binding energy by a variational method. Correlation between binding energy and localization of the charge carriers. The results show that the exciton ground state energy is size controlled.