Figure 2

XRD pattern and SEM images of ZnO nanoneedle arrays. (a) X-ray diffraction pattern of the ZnO nanoneedle arrays grown on FTO glass; the inset shows the magnified image of a wurtzite ZnO (002) peak with a FWHM of 0.22°. (b) Tilted-view FESEM image (40° tilted) of the ZnO nanoneedle arrays grown on FTO glass by hydrothermal method. (c) Cross-sectional-view FESEM image of the ZnO nanoneedle arrays.