Saturday, July 01, 2006

US Patent 7067237 - Selective Nanowire Growth

There is much interest in methods of forming arrays of nanostructures using traditional lithography approaches. The reason for this is that so much investment in terms of money and research has already been made in optical lithography that the industry is reluctant to switch to alternative methods. In addition, optical lithography is suited for mass production. This patent uses optical lithography for catalyst patterning, metal coating of the patterned catalyst to form a metal pattern, and nanowire growth on the metal pattern to achieve selectively patterned nanowire structures. Claim 1 reads:

1. A method for forming a pattern of a one-dimensional nanostructure, comprising the steps of: (i) coating a photocatalytic compound onto a substrate to form a photocatalytic film, and selectively exposing the photocatalytic film to light to form latent image centers for crystal growth; (ii) growing metal crystals by plating the latent pattern to form a metal pattern; and (iii) selectively growing a one-dimensional nanostructure on the metal pattern acting as a catalyst.