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Fabrication of ultralow-density quantum dots by droplet etching epitaxy

Published online by Cambridge University Press:  26 October 2017

Jiang Wu*
Department of Electronic and Electrical Engineering, University College London, London WC1E 7JE, U.K.
Zhiming M. Wang*
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, People’s Republic of China
Xinlei Li
MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People’s Republic of China
Yuriy I. Mazur
Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States of America
Gregory J. Salamo
Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States of America
a) Address all correspondence to these authors. e-mail:
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Isolated single quantum dots (QDs) enable the investigation of quantum-optics phenomena for the application of quantum information technologies. In this work, ultralow-density InAs QDs are grown by combining droplet etching epitaxy and the conventional epitaxy growth mode. An extreme low density of QDs (∼106 cm−2) is realized by creating low-density self-assembled nanoholes with the high temperature droplet etching epitaxy technique and then nanohole-filling. The preferred nucleation of QDs in nanoholes has been explained by a theoretical model. Atomic force microscopy and the photoluminescence technique are used to investigate the morphological and optical properties of the QD samples. By varying In coverages, the size of InAs QDs can be controlled. Moreover, with a thin GaAs cap layer, the position of QDs remains visible on the sample surface. Such a low density and surface signature of QDs make this growth method promising for single QD investigation and single dot device fabrication.

Invited Articles
Copyright © Materials Research Society 2017 

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Contributing Editor: Artur Braun



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