RENEWABLE ENERGY
The wettability of a solid surface is affected by the surface roughness and the surface chemical composition. It has been demonstrated that fractal rough surfaces or patterned microstructured pillar arrays can greatly alter the contact angle depending on the wettability of the original flat surface: for a hydrophilic surface, a super-hydrophilic property can be developed , and for a hydrophobic surface, a super-hydrophobic property can be produced. Very recently, the super-hydrophobic prOctober 21, 2011igned carbon nanotube arrays and Polyacrylonitrile nanofiber arrays. These studies show that a one-dimensional nanowire/rod array has a dramatic effect on the wettability of the surface. Unfortunately the detailed relationship between the wettability and structure parameters has not been investigated. In order to probe how the nanometer features affect the wettability of a surface, the most difficult task is to fabricate and quantify nanostructures that can be systematically varied. Here we would like to perform a systematic investigation on the wettability of vertically aligned Si nanorod arrays with different height s (aspect ratio s ) fabricated by the glancing angle deposition (GLAD) technique.
