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A study of nitrogen incorporation in pyramidal site-controlled quantum dots

Gediminas Juska*, Valeria Dimastrodonato, Lorenzo O Mereni, Agnieszka Gocalinska and Emanuele Pelucchi

Author Affiliations

Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland

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Nanoscale Research Letters 2011, 6:567  doi:10.1186/1556-276X-6-567

Published: 26 October 2011


We present the results of a study of nitrogen incorporation in metalorganic-vapour-phase epitaxy-grown site-controlled quantum dots (QDs). We report for the first time on a significant incorporation (approximately 0.3%), producing a noteworthy red shift (at least 50 meV) in some of our samples. Depending on the level of nitrogen incorporation/exposure, strong modifications of the optical features are found (variable distribution of the emission homogeneity, fine-structure splitting, few-particle effects). We discuss our results, especially in relation to a specific reproducible sample which has noticeable features: the usual pattern of the excitonic transitions is altered and the fine-structure splitting is suppressed to vanishing values. Distinctively, nitrogen incorporation can be achieved without detriment to the optical quality, as confirmed by narrow linewidths and photon correlation spectroscopy.

MOVPE; site-controlled quantum dots; dilute nitride semiconductors