SEM images of individual ZnO microcrystal, magnification image of tapered nanowire, and the oxidation process. SEM images of an individual ZnO microcrystal (a) before and (b) after oxidation at 500°C. (c) The magnification image of the tapered nanowire. (d) Illustration images of the metallic Zn transformed into ZnO microcavity during the oxidation process.
Lu et al. Nanoscale Research Letters 2014 9:178 doi:10.1186/1556-276X-9-178