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Title: Direct observation of doping incorporation pathways in self-catalytic GaMnAs nanowires

Doping mechanisms of Mn in GaAs nanowires (NWs) that have been grown self-catalytically at 600 °C by molecular beam epitaxy (MBE) are investigated using advanced electron microscopy techniques and atom probe tomography. Mn is found to be incorporated primarily in the form of non-magnetic tetragonal Ga{sub 0.82}Mn{sub 0.18} nanocrystals in Ga catalyst droplets at the ends of the NWs, while trace amounts of Mn (22 ± 4 at. ppm) are also distributed randomly in the NW bodies without forming clusters or precipitates. The nanocrystals are likely to form after switching off the reaction in the MBE chamber, since they are partially embedded in neck regions of the NWs. The Ga{sub 0.82}Mn{sub 0.18} nanocrystals and the low Mn concentration in the NW bodies are insufficient to induce a ferromagnetic phase transition, suggesting that it is difficult to have high Mn contents in GaAs even in 1-D NW growth via the vapor-liquid-solid process.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ; ; ;  [5] ;  [6] ;  [3] ;  [7]
  1. Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark)
  2. Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)
  3. Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, PL-02-668 Warszawa (Poland)
  4. Instituto de Ciencia de Materiales de Sevilla (CSIC-US), C/Américo Vespucio 49, 41092 Seville (Spain)
  5. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany)
  6. Solid State Physics and the Nanometer Structure Consortium, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden)
  7. (Sweden)
Publication Date:
OSTI Identifier:
22494699
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABUNDANCE; CATALYSTS; CRYSTAL DOPING; DROPLETS; ELECTRON MICROSCOPY; GALLIUM ARSENIDES; MANGANESE; MOLECULAR BEAM EPITAXY; NANOWIRES; PHASE TRANSFORMATIONS; PROBES; SOLIDS; TOMOGRAPHY; TRACE AMOUNTS; VAPORS