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Title: Hopkins-Skellam index and origin of spatial regularity in InAs quantum dot formation on GaAs(001)

We investigate the origin of the spatial regularity of arrays of InAs quantum dots (QDs) grown on GaAs(001). The Hopkins-Skellam index (HSI) is used with a newly developed calculation algorithm to quantify the spatial regularity both of QDs and of nm-sized surface reconstruction territories (SRTs) present in the In{sub x}Ga{sub 1−x}As wetting layer prior to QD nucleation. The SRT is the minimum extent of a surface reconstruction region needed for one QD to nucleate. By computing the evolving HSI of SRTs from sequences of in situ scanning tunnelling microscopy images during growth, we find that the spatial regularity of QDs is traced back to that of the (n × 3) SRTs as early as 0.6 monolayers of InAs coverage. This regularity is disturbed by the (n × 4) SRTs which appear at higher coverage. The SRT approach is discussed in comparison to conventional capture zone theories of surface growth.
Authors:
;  [1] ;  [2]
  1. Centre for Collaborative Research, National Institute of Technology, Anan College, Anan, Tokushima 774-0017 (Japan)
  2. Department of Physics, University of Warwick, Coventry CV47AL (United Kingdom)
Publication Date:
OSTI Identifier:
22402844
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTROSCOPY; ALGORITHMS; COMPARATIVE EVALUATIONS; CRYSTAL GROWTH; CRYSTAL STRUCTURE; GALLIUM ARSENIDES; IMAGES; INDIUM ARSENIDES; LAYERS; NUCLEATION; QUANTUM DOTS; SCANNING TUNNELING MICROSCOPY; SURFACES; X-RAY SPECTROSCOPY