Argonne National Laboratory

Research Highlight | Materials Science

3D multi-modal nanoscale structural imaging of an III-V nanowire
In a study published in Nano Letters, researchers found the penetrating nature of X-ray radiation, together with the relaxed constraints of multiangle Bragg projection ptychography, will enable the in operando imaging of nanowire devices.
Multiangle Bragg projection ptychography reconstruction of the 011̅0 peak. (a) A cut into the reconstruction volume and (b) a 2D slice reveal rapidly varying phase features. A line cut of (c) phase and (d) intensity from the center of the nanowire compares two independent reconstructions with different starting guesses to test reproducibility. Correlation tables for every point in the two independent reconstructions show strong phase correlation. (e) Note that the wrapping in phase around 2π results in a concentration of points at the top left and bottom right corners, which should fall along the correlation axis. (f) The two reconstructions show a lesser degree of amplitude correlation.

Scientific Achievement

In a single III-V nanowire, the 3D distribution of both strain and stacking defects was measured using coherent X-rays, revealing structural heterogeneity from nano- to micro-meter scales.

Significance and Impact

Structural features that determine the performance of advanced optoelectronic nanodevices can be imaged by a new coherent X-ray Bragg ptychography method suitable for studies in operando.

Research Details

  • At the NSLS-II 3-ID beamline, high-resolution nanodiffraction measurements were made of a single InGaAs nanowire at two different Bragg peaks with different structural sensitivity.
  • A new multi-angle Bragg projection ptychography method was used to make 3D images of structure down to a scale of 3 nm, with a robust algorithm insensitive to scan registration.

Work was performed at Argonne and Brookhaven national laboratories.

DOI: 10.1021/acs.nanolett.7b04024

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