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Title: Annealing-induced change in quantum dot chain formation mechanism

Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Physics and Astronomy, Brigham Young University, Provo UT 84602 (United States)
  2. Department of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States)
  3. IPG Photonics Corporation, Oxford, MA 01540 (United States)
Publication Date:
OSTI Identifier:
22420217
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 12; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; ARSENIC; DEPOSITS; GALLIUM ARSENIDES; INDIUM; INDIUM ARSENIDES; OPTICAL PROPERTIES; QUANTUM DOTS; TRANSMISSION ELECTRON MICROSCOPY