Available Technology

BSA 14-35: Nanowires and Methods of Making

There is a significant interest in studying bismuth nanowires for use in thermoelectric applications. Unfortunately, the difficulty in scalable fabrication of high quality and single crystalline bismuth nanowires hinders its production. The present invention provides a method of fabricating vertical single crystalline bismuth nanowires by vacuum thermal evaporation in high yields at room-temperature. The simplicity of the technique opens a new avenue for the growth of nanowire arrays of a variety of materials.
Patent Abstract: 
In the present invention, room-temperature growth of an array of out-of-plane nanowires are formed by vacuum thermal evaporation of a material over a choice of arbitrary substrate coated with a thin interlayer of nanoporous film. Driven by the release of excessive surface energy, the nanowire growth is the result of spontaneous and continuous expulsion of nanometer-sized material, such as bismuth, domains from the sputter-deposited film, such as vanadium, pores. A catalyst is not needed for the fabrication of these nanowires. The absence of a catalyst in this method eliminates any unwanted diffusion of catalyst atoms into the nanostructures, thus allowing a route for the growth of nanostructure of higher purity and better controlled properties.
Overall, the formation of nanowires involves no apparent catalyst and follows a unique and novel mechanism. The technique is scalable and generally applicable for scalable growth of one-dimensional nanostructures of various other materials with moderate melting points.
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