Investigation of oscillator strength, absorption coefficients and refractive index changes of ZnSe/ZnS non-concentric core–shell quantum dot

The aim of this work is to study the optical properties of ZnSe/ZnS non-concentric core–shell quantum dots (CSQDs). The numerical method used in this work is based on a combination of coordinate transformation and finite difference method (FDM) to solve the three dimensions of the Schrödinger equation. The optical properties are obtained using the compact density matrix formalism. The influence of different dimensions of the non-concentric CSQD, the position of a core material and the effect of different values of the incident optical intensity I on the optical properties of the CSQD are investigated. The results obtained indicate that the oscillator strength, absorption coefficient and refractive index changes are strongly dependent on the size of the CSQD. The magnitude of both the total absorption coefficient and the refractive index decreased as the incident optical intensity increased. In addition, the resonance peaks for the absorption coefficient and refractive index changes shift towards higher energies when we move from concentric to non-concentric core–shell quantum dots.