AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuM

Paper SS2-TuM3
Nanocarpet Effect: Formation and Characterization of Watermarks on Aligned Silicon Nanorod Arrays

Tuesday, November 14, 2006, 8:40 am, Room 2004

Session: Water-Surface Interactions
Presenter: Y.P. Zhao, University of Georgia
Authors: Y.P. Zhao, University of Georgia
J.G. Fan, University of Georgia
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When a water drop spreads on an aligned silicon nanorod surface prepared by glancing angle deposition, a watermark developed on the surface after water evaporated due to the bundling of nanorods. The watermark radius R follows a simple power law relationship with the water volume @OMEGA@ as R ~ @OMEGA@@super n@. The scaling exponent n, in the vicinity of 1/3, increases when the nanorods height decreases. This behavior is attributed to the competition of evaporation and spreading of a water droplet during the spreading process. The size of the bundled nanorod cluster depends not only on the nanorod height, but also on the location in the watermark. The cluster size almost remains as a constant near the center, and then it decreases with the distance from the center. This phenomenon can be qualitatively interpreted through the change of the total free energy during the precursor invading the nanorod array, by considering the contribution from the mechanical energy change due to the bending and clustering of nanorods.