Spectrum and tunneling in self-assembled quantum dots

We present analytical results for the tunneling escape rate for nanoscale quantum dots (QD's). It is shown that tunneling from excited states with nonzero angular momentum is suppressed. The tunneling from the states with zero angular momentum is described by a universal expression where only the preexponential factor is dependent of a particular model for a QD. The result is used to calculate the photocurrent spectrum in QD arrays. The expression for the photocurrent is reduced to a simple formula with few model-dependent parameters. The results are in quantitative agreement with experimental data. Average electron ground-state energy of a QD at the flatband condition is extracted from the best fit.