Coherent x-ray diffraction imaging of ZnO nanostructures under confined illumination

Abstract

Coherent x-ray diffraction imaging has been used to study a single ZnO nanorod in a confined illuminating condition. The focused beam size is smaller than the length of the nanorod, and the diffraction intensity is strongly dependent on the illumination position. The density maps show that the nanorod width in the radial direction is around 210 nm and has a length of 1.5μm, in agreement with the scanning electron microscope measurement. Reconstructed phase maps show a maximum phase change of 0.8 radians. The reconstructed direct space structures reveal the exit wavefront profile, which includes that of the focused x-ray beam. The beam profile presents in reconstructions some 'hill and valley' surface features with a typical size of a few tens of nanometres and are attributed to the noise due to the slow variation of the focused beam intensity along the boundary. A single ZnO tetrapod has been investigated with the same method to recover the beam profile in the horizontal direction. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.