Low-temperature oxidation effects on the morphological and structural properties of hexagonal Zn nanodisks

Abstract

Ambient-atmosphere oxidation in the temperature range of 90-450$^{\circ}$C was performed over Zn films composed by well-faceted hexagonal nanodisks, which were deposited by thermal evaporation. Morphological and structural properties of oxidized Zn nanodisks were studied by scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman scattering measurements. It was found that Zn nanodisks keep its original shape only when they are annealed at 90 or 150$^{\circ}$C. Smooth oxidation ocurred only on the rectangular faces of Zn nandodisks heated at 150$^{\circ}$C. Thermal oxidation at 250$^{\circ}$C favored growth of ZnO nanoneedles over the surface of the Zn nanodisks. Hexagonal-shape of Zn nanodisks was transformed completely into a complex morphology composed by different shaped particles, with further increase in oxidation temperature to 450$^{\circ}$C.