Precisely positioned nanowhiskers and nanowhisker arrays and method for preparing them

摘要

A nanoengineered structure comprising an array of more than about 1000 nanowhiskers on a substrate in a predetermined spatial configuration, for use for example as a photonic band gap array, wherein each nanowhisker is sited within a distance from a predetermined site not greater than about 20% of its distance from its nearest neighbour. To produce the array, an array of masses of a catalytic material are positioned on the surface, heat is applied and materials in gaseous form are introduced such as to create a catalytic seed particle from each mass, and to grow, from the catalytic seed particle, epitaxially, a nanowhisker of a predetermined material, and wherein each mass upon melting, retains approximately the same interface with the substrate surface such that forces causing the mass to migrate across said surface are less than a holding force across a wetted interface on the substrate surface.

主权项

1. A method for producing a structure including at least one nanowhisker on a planar substrate, the method comprising:
providing the planar substrate of a predetermined material, providing at least one mass of a metal catalytic material on a surface of the substrate at a predetermined position on the surface, after the step of providing the at least one mass, annealing at a first temperature the at least one mass of metal catalytic material located on the surface of the planar substrate to alloy at least one other metal material with the at least one mass of metal catalytic material to create a metal alloy catalytic seed particle from each said mass and to create a wetted interface between the surface of the substrate and the metal alloy catalytic seed particle, and after the step of annealing during which the metal alloy catalytic seed particle is created, epitaxially growing at a second temperature different from the first temperature a nanowhisker of a predetermined material from the metal alloy catalytic seed particle located on the substrate by introducing a first precursor gas flow to the metal alloy catalytic seed particle, wherein each said mass is such that during the formation of the catalytic seed particle, forces causing the mass to migrate across said surface of the planar substrate are less than a holding force across the wetted interface between the surface of the planar substrate and the metal alloy catalytic seed particle.