Scanning probe microscopy-based characterization of ZnO nanorods

We apply scanning probe microscopy (SPM) to study the morphology and electrical properties of vertical zinc oxide nanorods grown by hydrothermal methods on silicon substrates. It is demonstrated that - against the intuition - SPM techniques can indeed be used to study such fragile high-aspect ratio semiconductor nanorods. Atomic-force microscopy (AFM) operating in tapping mode yields - via the analysis of the height histograms calculated from AFM images - easy access to the height fluctuations in the nanorod ensemble. High-resolution AFM images reveal the three-dimensional shape of the nanorods including transition facets between the (0001) top terrace and the {10-10} side facets. Further, we were able to acquire current-voltage curves of individual nanorods by conductive atomic force microscopy (CAFM) operating in contact mode.