Selective optical pumping of charged excitons in unintentionally doped InAs quantumdots

Abstract

We have investigated the selective optical pumping of charged excitonic species in a samplecontaining quantum dots of different sizes and low areal density by photoluminescence andexcitation of the photoluminescence microspectroscopy. We study the selective opticalexcitation of negatively charged excitons as an alternative to commonly usedelectrical methods. We demonstrate that under resonant excitation in impurityrelated bands, the selective pumping efficiency can be as high as 85% in smallquantum dots having one electron shell and emitting at around 930 nm, and around65% in big quantum dots having four electron shells and emitting at 1160 nm.