Electric field effects on excitons in cylindrical quantum dots with asymmetric axial potential. Influence on the nonlinear optical properties

摘要

The exciton binding energy in an asymmetrical GaAs-Ga _(1-x) Al _xAs cylindrical quantum dot is studied with the use of the effective mass approximation and a variational calculation procedure. The influence on these properties of the application of an electric field along the growth direction of the cylinder is particularly considered. It is shown that for zero applied electric field the binding energy is a decreasing function of the quantum dot radius and height. Given a fixed geometric configuration, this quantity becomes a decreasing function of the electric field strength. In addition, the exciton-related nonlinear optical absorption and optical rectification resonant peaks are reported as functions of quantum dots dimensions and the aluminum molar fraction in the potential barrier regions.