Dynamic spatial ordering of thin film nanostructures by rapid spatio-temporal surface modulations

Abstract

AbstractWe present novel results showing that the application of a rapid spatio-temporal surface modulation in-situ with film deposition directs the assembly of ordered nanostructures. Co nanoclusters of approximately 50 nm in size were assembled into one-dimensionally ordered arrays spaced 400 nm apart on Si (100) substrates during film growth of a 0.5 nm thick film. This ordered arrangement was achieved under e-beam evaporation of Co with simultaneous two-beam pulsed laser interference irradiation. The ordering length scale was consistent with the theoretical two-beam fringe spacing. For a thicker Co film, the particles were irregularly shaped, like that of a rapidly solidified liquid-like structure. From this evidence, the mechanism for ordering is partly attributed to thermal effects due to the spatially periodic laser interference heating of the cobalt nanoparticles. This dynamic in-situ process, without the need of any pre-or post-patterning of the substrate or film, is promising as an economical and simple approach to assemble ordered nanostructured films. The author can be reached via e-mail at ramkik@wuphys.wustl.edu