Figure 1.
a The geometrical configuration of ion-beams sputtering and Fe doping process. b XRD results of as-synthesized sample. c SEM images of Zn0.989Fe0.011O NDs. d TEM image of a single Zn0.989Fe0.011O nanoneedle. e High-resolution TEM image of the nanoneedle and f the corresponding selected area electron diffraction pattern