10 6 years extrapolated hole storage time in GaSb∕AlAs quantum dots

Abstract

A thermal activation energy of 710meV for hole emission from InAs∕GaAs quantum dots (QDs) across an Al0.9Ga0.1As barrier is determined by using time-resolved capacitance spectroscopy. A hole storage time of 1.6s at room temperature is directly measured, being three orders of magnitude longer than a typical dynamic random access memory (DRAM) refresh time. The dependence of the hole storage time in different III–V QDs on their localization energy is determined and the localization energies in GaSb-based QDs are calculated using eight-band k⋅p theory. A storage time of about 106years in GaSb∕AlAs QDs is extrapolated, sufficient for a QD-based nonvolatile (flash) memory.