450 meV hole localization in GaSb/GaAs quantum dots

Abstract
The electronic properties of self-organized GaSb quantum dots (QDs) embedded in GaAs n+p diodes were investigated by capacitance–voltage and deep level transient spectroscopy. The localization energy of the hole ground state is 450 meV. State filling lowers the activation energy to 150 meV for completely charged QDs containing 15 holes. The hole retention time at room temperature for a single hole per QD is extrapolated to be in the microsecond range, about five orders of magnitude longer than in In(Ga)As/GaAs QDs. Hence, we consider GaSb/GaAs to be a suitable material system for future QD memory applications which require long storage times.