In situ photoluminescence study of uncapped InAs/GaAs quantum dots
AbuWaar, Ziad Y; Marega, E; Mortazavi, M; Salamo, G J; AbuWaar, Ziad Y; Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA ; Department of Physics, University of Jordan, Amman, 11942, Jordan; Marega, E; Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA ; Departamento de Física e Ciência dos Materiais, Instituto de Física de São Carlos-USP, São Carlos SP 13560-970, Brazil; Mortazavi, M; Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA; Salamo, G J; Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA
Журнал:
Nanotechnology
Дата:
2008-08-20
Аннотация:
We present a study of photoluminescence (PL) from uncapped non-oxidized and oxidized InAs quantum dots (QDs) on GaAs substrate as a function of the thickness of a GaAs capping layer. A photoluminescence system in ultra-high vacuum that was coupled onto a molecular beam epitaxy chamber was used in order to avoid the oxidation of the quantum dot surface. We report for the first time a PL emission obtained from uncapped as-grown (non-oxidized) InAs QDs. We also report a dramatic change in the energy position and intensity of the PL as the quantum dots get closer to the top surface of the structure and make a direct comparison between the PL from non-oxidized and oxidized uncapped InAs/GaAs QDs. On the basis of these observations, we offer a physical explanation, based on oxidized versus non-oxidized uncapped QDs, for the discrepancies between previously reported results.
448.9Кб