The present invention is directed to methods to produce, process, and exploit nanomaterials, and particularly elongated nanowire materials. The invention provides a method for producing nanowires that includes providing a thin film of a catalyst material with varying thickness on a substrate, heating the substrate and thin film, such that the thin film disassociates at the relatively thinner regions and vapor depositing a semiconductor onto the substrate to produce nanowires. A method is also provided in which two or more thin films of different materials are overlayed over a substrate, selectively etching the first underlying thin film to create a plurality of islands of the second thin film that mask portions of the first thin film and expose other portions and growing nanowires on the first thin film. Additional methods for producing nanowires are provided.