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Title: Coherent x-ray diffraction from quantum dots

Coherent x-ray diffraction is a new experimental method for studying perfect and imperfect crystals. Instead of incoherent averaging, a coherent sum of amplitudes produces a coherent diffraction pattern originating from the real space arrangement of the sample. We applied this method for studying quantum dot samples that were specially fabricated GeSi islands of nanometer size and in a regular array embedded into a Si substrate. A coherent beam was focused by special Kirkpatric-Baez optics to a micrometer size. In the experiment it was observed that such a microfocused coherent beam produced coherent diffraction pattern with Bragg spots and broad diffuse maxima. The diffuse peak breaks up into a fine speckle pattern. The grazing incidence diffraction pattern has a typical shape resulting from the periodic array of identical islands. We used this diffraction pattern to reconstruct the average shape of the islands using a model independent approach.
Authors:
 [1] ;  [2] ; ; ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. HASYLAB, DESY, Notkestr. 85, Hamburg D-22607 (Germany)
  2. (United States)
  3. Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801 (United States)
  4. Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen (Switzerland)
  5. ESRF, BP 220, 38043 Grenoble (France)
  6. Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)
  7. (Austria)
  8. Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz (Austria)
Publication Date:
OSTI Identifier:
20719069
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 71; Journal Issue: 24; Other Information: DOI: 10.1103/PhysRevB.71.245302; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTALS; GERMANIUM ALLOYS; OPTICS; PERIODICITY; QUANTUM DOTS; SCATTERING AMPLITUDES; SEMICONDUCTOR MATERIALS; SILICON ALLOYS; SUBSTRATES; X RADIATION; X-RAY DIFFRACTION