Carbon nanogears and nanotori via combustion flames

Self-organized micro-/nanostructures are obtained by a combustion flame of ethanol and a mixture of ethanol and nickel acetate. Microscopic analyses of the depositions on glass slides and Si wafers reveal that a variety of micro-/nanostructures are formed in the shapes of quadrilaterals, hexagons, nanogears, nanotori, spheres and anomalous structures. Raman spectra show two peaks at ~1352 cm^-1 (D) and ~1608 cm^-1 (G), respectively, which indicate that these structures are made of graphic carbons. Among these structures, carbon nanogears and nanotori were fabricated with the combustion flame technique for the first time and are with the potential to be used in nanomachines as gears and tyre. Although the growth of these patterns can be attributed to self-organization, the fact that they grow along with certain directions shows a directed self-organization nature.