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Title: Impact of the non-planar morphology of pre-patterned substrates on the structural and electronic properties of embedded site-controlled InAs quantum dots

We present an experimental and theoretical analysis of the influence of a surface nanopattern on the properties of embedded InAs/GaAs quantum dots (QD). In particular, we analyze QDs grown on nanoimprint lithography (NIL) patterned grooves and investigate the influence of the non-planar surface morphology on the size, shape, strain distribution, and electronic structure of the embedded QDs. We show that the height reduction of InAs QDs during GaAs capping is significantly less pronounced for the QDs grown on the pattern than for the self-assembled QDs. Furthermore, the pattern has a strong impact on the strain and composition profile within the QD. The experimentally observed strain distribution was successfully reproduced with a three-dimensional model assuming an inverse-cone type composition gradient. Moreover, we show that the specific morphology of the QDs grown in the grooves gives rise to an increase of the vertically polarized photoluminescence emission which was explained by employing 8-band k.p calculations. Our findings emphasize that the surface curvature of the pattern not only determines the nucleation sites of the QDs but also has a strong impact on their morphological properties including shape, size, composition profile, and strain distribution. These properties are strongly cross-correlated and determine the electronic and opticalmore » characteristics of the QDs.« less
Authors:
; ; ;  [1] ;  [2]
  1. Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere (Finland)
  2. Paul-Drude-Institut f√ľr Festk√∂rperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)
Publication Date:
OSTI Identifier:
22259303
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 17; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ELECTRONIC STRUCTURE; GALLIUM ARSENIDES; INDIUM ARSENIDES; MORPHOLOGY; NUCLEATION; PHOTOLUMINESCENCE; QUANTUM DOTS; STRAINS; SUBSTRATES