Direct observation of tunneling emission to determine localization energies in self-organized In(Ga)As quantum dots

We report direct observation of tunneling emission of electrons and holes from In(Ga)As/GaAs QDs in time resolved capacitance spectroscopy. From the dependence of the tunneling time constant on the external electric field the important entire localization energies of electron and holes in In(Ga)As QDs are determined with high accuracy. The results yield electron and hole localization energies of (260±20)meV and (210±20)meV, respectively, which is in excellent agreement with 8-band k·p theory.