Spherical quantum dot with added parabolic confinement as a nanoscale tunable radiation detector

We have calculated the optical absorption matrix elements for a spherical silicon quantum dot embedded in silicon dioxide with the addition of a parabolic potential which is used to tune the bound state energy levels. The photon absorption from the ground state to the excited states was calculated as a function of the parabolic potential curvature constant and the dot radius which varied between 2 and View the MathML source. The results show that we can tune the wavelength in the entire visible range. Furthermore, the absorption cross section was found to change by several orders of magnitude with increasing parabolic potential curvature constant. For large parabolic curvature constant the transition move out of the visible range, and the number of allowed transition increased with the dot radius.