Electronic states tuning of InAs self-assembled quantum dots

3 páginas, 3 figuras.-- PACS: 778.66.Fd, 78.55.Cr, 81.15.Hi, 81.05.Ea, 73.21.-b, 85.35.BeWe demonstrate the dimensional tuning of InAs self-assembled quantum dots (QDs) by changing the growth kinetics during the capping of InAs islands with GaAs. Modifying the growth sequence during the capping of InAs islands, allows us to tune the thickness and lateral dimensions of the QDs while keeping the wetting layer thickness constant. Using the same method but embedding the tuned InAs islands into AlAs layers allows to further blueshift the photoluminescence emission to higher energies while keeping the wetting layer thickness constant. The main process responsible for the QDs size modification is consistent with a kinetically controlled materials redistribution of the InAs islands that minimizes the energy of the epitaxial layers at the start up of the GaAs capping deposition.The authors want to acknowledge the financial support of QUEST an NSF-Science and Technology center (DMR No. 91-20007), the Linköping University (POH), the Deutsche Forschungsgemeinschaft (PJW) and the Spanish Ministry of Education and Science (JMG) for financial support.Peer reviewe

Enhancement of the Binding Energy of Charged Excitons in Disordered Quantum Wires

Negatively and positively charged excitons are identified in the spatially-resolved photoluminescence spectra of quantum wires. We demonstrate that charged excitons are weakly localized in disordered quantum wires. As a consequence, the enhancement of the "binding energy" of a charged exciton is caused, for a significant part, by the recoil energy transferred to the remaining charged carrier during its radiative recombination. We discover that the Coulomb correlation energy is not the sole origin of the "binding energy", in contrast to charged excitons confined in quantum dots.Comment: 4 Fig

Pure luminescence transitions from a small InAs/GaAs quantum dot exhibiting a single electron level

2 páginas, 3 figuras.Pure photoluminescence spectra originating from a single InAs/GaAs quantum dot, which is small enough to possess only one single-electron level, are demonstrated. A symmetric fine structure of the exciton and the biexciton is observed.Peer reviewe