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Title: Coherent x-ray diffraction from quantum dots

Abstract

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

Citation Formats

Vartanyants, I.A., Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801, Robinson, I. K., Onken, J.D., Pfeifer, M.A., Williams, G.J., Pfeiffer, F., Metzger, H., Zhong, Z., Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz, and Bauer, G. Coherent x-ray diffraction from quantum dots. United States: N. p., 2005. Web. doi:10.1103/PhysRevB.71.245302.
Vartanyants, I.A., Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801, Robinson, I. K., Onken, J.D., Pfeifer, M.A., Williams, G.J., Pfeiffer, F., Metzger, H., Zhong, Z., Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz, & Bauer, G. Coherent x-ray diffraction from quantum dots. United States. doi:10.1103/PhysRevB.71.245302.
Vartanyants, I.A., Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801, Robinson, I. K., Onken, J.D., Pfeifer, M.A., Williams, G.J., Pfeiffer, F., Metzger, H., Zhong, Z., Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz, and Bauer, G. 2005. "Coherent x-ray diffraction from quantum dots". United States. doi:10.1103/PhysRevB.71.245302.
@article{osti_20719069,
title = {Coherent x-ray diffraction from quantum dots},
author = {Vartanyants, I.A. and Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801 and Robinson, I. K. and Onken, J.D. and Pfeifer, M.A. and Williams, G.J. and Pfeiffer, F. and Metzger, H. and Zhong, Z. and Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz and Bauer, G.},
abstractNote = {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.},
doi = {10.1103/PhysRevB.71.245302},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 24,
volume = 71,
place = {United States},
year = 2005,
month = 6
}
  • The missing data problem, i.e., the intensities at the center of diffraction patterns cannot be experimentally measured, is currently a major limitation for wider applications of coherent diffraction microscopy. We report here that, when the missing data are confined within the centrospeckle, the missing data problem can be reliably solved. With an improved instrument, we recorded 27 oversampled diffraction patterns at various orientations from a GaN quantum dot nanoparticle and performed quantitative image reconstruction from the diffraction intensities alone. This work in principle clears the way for single-shot imaging experiments using x-ray free electron lasers.
  • No abstract prepared.
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