Exciton binding energies and absorption intensities in quantum dots

Exciton binding energies and wavefunctions are calculated for spherical quantum dots of GaAs embedded in GaAlAs for a range of radii from 10 to 200 AA. The calculations use the quantum Monte Carlo method which allows the finite potential barriers in this system to be treated in a straightforward manner. The exciton binding energy and absorption intensity are found to pass through a maximum for dots of approximately 30 AA radius; strong optical non-linearities would be expected in dots of this size.