Nonlinear optical properties of lens-shaped core/shell quantum dots coupled with a wetting layer: effects of transverse electric field, pressure, and temperature

In this study, we numerically determined the intra-band transition lifetime of carriers as well as, the linear, nonlinear, and total absorption coefficients fro lens-shaped core/shell quantum dot structures. Our computations considered the combined effects of the wetting layer, pressure, applied transverse electric field, temperature, and core/shell sizes. By using suitable choices for these parameters, we found that a red or blue shift in the energy of the absorption spectrum could be achieved. In addition, the largest absorption coefficient was obtained when an intense transverse electric field was applied along the diagonal of the cross section of the structure considered. Hence, the magnitude of the absorption coefficient increased by 50%. Moreover, our results showed that the transition lifetime of the carriers decreased as the temperature increased, whereas it increased as the pressure increased. Comparative analysis of a semi-spherical core/shell quantum dot system showed that the transition lifetime was shorter than that of the lens-shaped core/shell quantum dot structure, which was 255 ns.