US Patent 7402445 - Nanotip fabrication using film melting and cooling

http://www.freepatentsonline.com/7402445.html

This patent from Wayne State University teaches a novel method for forming a nanotip useful as an electron emitter by laser irradiation of semiconductor (e.g. Si, Ge, GaAs, etc.) thin films followed by cooling. Claim 1 reads:

1. A method of forming a nano-structure, the method comprising:

irradiating an area on a first surface of a thermal conductive film to melt the area across the film, the film being insulated at a second surface thereof to provide two-dimensional heat transfer across the film, the liquid density of the film being greater than the solid density thereof; and

cooling the area inwardly from the periphery thereof to form the nano-structure having an apical nano-tip.