Theoretical studies on third nonlinear optical susceptibility in CdTe-CdS-ZnS core-shell-shell quantum dots

In this work, we analyze the optical properties of spherical CdTe-CdS-ZnS core-shell-shell quantum dots (QDs). Under the framework of the effective mass envelope function theory, the electron and hole energy states and wave functions are computed by solving the three-dimensional Schrodinger equation. We also calculate the nonlinear susceptibilities associated with inter-sub-band transitions in the conduction band for CdTe-CdS-ZnS spherical QDs. We theoretically investigate the third-order susceptibilities as a function of the core, shell radii, pump photo-energy and time relaxation. The numerical calculations reveal that QD size plays a fundamental role in determining the nonlinear optical properties of QDs. The susceptibilities have pronounced single peaks (resonance) and depend strongly on the parameters already mentioned. Our theoretical study shows that susceptibility peaks are red-shifted by increasing the shell width, and the magnitude of susceptibility increases with pump photon energy. Our numerical results may open a new window in optoelectronic device conceptions as well as development of their various applications.