Tunneling emission from self-organized In(Ga)As∕GaAs quantum dots observed via time-resolved capacitance measurements

Abstract

The observation of tunneling emission of electrons and holes from $\mathrm{In}(\mathrm{Ga})\mathrm{As}∕\mathrm{GaAs}$ quantum dots in time-resolved capacitance measurements is reported. The electron and hole ground-state localization energies are determined as $(290\ifmmode\pm\else\textpm\fi{}30)\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ and $(210\ifmmode\pm\else\textpm\fi{}20)\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, respectively. These energies are in excellent agreement with predictions from eight-band $\mathbf{k}∙\mathbf{p}$ theory. Based on the localization energies, we estimate the escape time for thermal excitation at room temperature as $\ensuremath{\sim}200\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ for electrons and $\ensuremath{\sim}0.5\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ for holes in case of a zero-electric-field situation. The electric-field dependence of the tunneling emission is investigated in detail.