Nano wheat fields prepared by plasma-etching gold nanowire-containing membranes

The template method is a general approach for preparing nanomaterials, in particular nanowires and nanotubes. The ability to control the dimensions of the nanowires and tubes obtained is an important feature of the template method. Diameter can be controlled at will by varying the diameter of the pores in the template membrane. The lengths of the nanostructures can be controlled by varying the thickness of the template membrane. We report here a new approach for effectively controlling the lengths of template-synthesized nanostructures. This method is illustrated with gold nanowires deposited within the pores of a polycarbonate template membrane. When these nanowire-containing membranes are exposed to an O-2 plasma, the polymer at the membrane surface is selectively removed, thus exposing the ends of the Au nanowires. The length of the exposed nanowire can be controlled at will by varying the plasma etch time. The protruding ends of the Au nanowires resemble wheat fields.