Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging
Coherent x-ray diffraction imaging is used to measure diffraction patterns from individual highly defective nanowires, showing a complex speckle pattern instead of well-defined Bragg peaks. The approach is tested for nanowires of 500 nm diameter and 500 nm height predominately composed by zinc-blend...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2016-01-01
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| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/18/6/063021 |
| _version_ | 1827873685972713472 |
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| author | Arman Davtyan Andreas Biermanns Otmar Loffeld Ullrich Pietsch |
| author_facet | Arman Davtyan Andreas Biermanns Otmar Loffeld Ullrich Pietsch |
| author_sort | Arman Davtyan |
| collection | DOAJ |
| description | Coherent x-ray diffraction imaging is used to measure diffraction patterns from individual highly defective nanowires, showing a complex speckle pattern instead of well-defined Bragg peaks. The approach is tested for nanowires of 500 nm diameter and 500 nm height predominately composed by zinc-blende (ZB) and twinned zinc-blende (TZB) phase domains. Phase retrieval is used to reconstruct the measured 2-dimensional intensity patterns recorded from single nanowires with 3.48 nm and 0.98 nm spatial resolution. Whereas the speckle amplitudes and distribution are perfectly reconstructed, no unique solution could be obtained for the phase structure. The number of phase switches is found to be proportional to the number of measured speckles and follows a narrow number distribution. Using data with 0.98 nm spatial resolution the mean number of phase switches is in reasonable agreement with estimates taken from TEM. However, since the resolved phase domain still is 3–4 times larger than a single GaAs bilayer we explain the non-ambiguous phase reconstruction by the fact that depending on starting phase and sequence of subroutines used during the phase retrieval the retrieved phase domain host a different sequence of randomly stacked bilayers. Modelling possible arrangements of bilayer sequences within a phase domain demonstrate that the complex speckle patterns measured can indeed be explained by the random arrangement of the ZB and TZB phase domains. |
| first_indexed | 2024-03-12T16:40:44Z |
| format | Article |
| id | doaj.art-aeba6b8ada6a4731823e931077d1304f |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:40:44Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-aeba6b8ada6a4731823e931077d1304f2023-08-08T14:31:35ZengIOP PublishingNew Journal of Physics1367-26302016-01-0118606302110.1088/1367-2630/18/6/063021Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imagingArman Davtyan0Andreas Biermanns1Otmar Loffeld2Ullrich Pietsch3Faculty of Science and Engineering, University of Siegen , 57068 Siegen, GermanyFaculty of Science and Engineering, University of Siegen , 57068 Siegen, GermanyFaculty of Science and Engineering, University of Siegen , 57068 Siegen, GermanyFaculty of Science and Engineering, University of Siegen , 57068 Siegen, GermanyCoherent x-ray diffraction imaging is used to measure diffraction patterns from individual highly defective nanowires, showing a complex speckle pattern instead of well-defined Bragg peaks. The approach is tested for nanowires of 500 nm diameter and 500 nm height predominately composed by zinc-blende (ZB) and twinned zinc-blende (TZB) phase domains. Phase retrieval is used to reconstruct the measured 2-dimensional intensity patterns recorded from single nanowires with 3.48 nm and 0.98 nm spatial resolution. Whereas the speckle amplitudes and distribution are perfectly reconstructed, no unique solution could be obtained for the phase structure. The number of phase switches is found to be proportional to the number of measured speckles and follows a narrow number distribution. Using data with 0.98 nm spatial resolution the mean number of phase switches is in reasonable agreement with estimates taken from TEM. However, since the resolved phase domain still is 3–4 times larger than a single GaAs bilayer we explain the non-ambiguous phase reconstruction by the fact that depending on starting phase and sequence of subroutines used during the phase retrieval the retrieved phase domain host a different sequence of randomly stacked bilayers. Modelling possible arrangements of bilayer sequences within a phase domain demonstrate that the complex speckle patterns measured can indeed be explained by the random arrangement of the ZB and TZB phase domains.https://doi.org/10.1088/1367-2630/18/6/063021coherent diffraction imagingphase retrievalstacking faultsnanowires |
| spellingShingle | Arman Davtyan Andreas Biermanns Otmar Loffeld Ullrich Pietsch Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging New Journal of Physics coherent diffraction imaging phase retrieval stacking faults nanowires |
| title | Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging |
| title_full | Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging |
| title_fullStr | Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging |
| title_full_unstemmed | Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging |
| title_short | Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging |
| title_sort | determination of the stacking fault density in highly defective single gaas nanowires by means of coherent diffraction imaging |
| topic | coherent diffraction imaging phase retrieval stacking faults nanowires |
| url | https://doi.org/10.1088/1367-2630/18/6/063021 |
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