A carrier escape study from InAs self-assembled quantum dots by photocurrent measurement

We report investigations of the carrier escape from InAs self-assembled quantum dots. Based on measurements of the temperature-dependent photocurrent, the escape of photoexcited carriers is found to be dominated by the hole escape process. The main path for this hole escape was further clarified, which is a thermally assisted hole tunneling, from the dot level to the GaAs barrier via the wetting layer as an intermediate state. The size selective tunneling effect and the carrier redistribution effect are discussed and compared with temperature-dependent photoluminescence measurements.