nanosurface 2007-12-11 01:48
美国化学学会纳米科技亮点文献聚焦（ACS Nano Picks）01
[size=4][b]Decorating nanowires using Joule heating[/b][/size]
By
[color=Blue]Dr. Etienne de Poortere[/color]
Columbia University
[b]Article Title:[/b] Selective Surface Functionalization of Silicon Nanowires via Nanoscale Joule Heating
Article Citation: [b][i]Nano Letters,[/i][/b] 2007, [b]7[/b](10), 3106-3111
[b]Article Review:[/b]
In this article, the authors demonstrate an original method for the selective attachment of nanoparticles to silicon nanowires. Starting from an array of parallel nanowires defined by electron-beam lithography on a silica substrate, they first coat the surface with a uniform PTFE layer. They then drive a high electrical current through a subset of the wires, heating them to ~800 K, which in turn causes the selective desorption of the protective Teflon coating from the heated wires. The deprotected lines are then functionalized with gold nanoparticles, which do not bind to the other PTFE-coated nanowires.
This innovative method offers a simple means of selectively functionalizing nanostructures on substrates. Currently, the main alternative is dip-pen nanolithography, which, although more versatile, requires sophisticated equipment and good control of the solvent meniscus formed between probe tip and substrate. The beauty of the selective desorption technique described in this paper lies in its simplicity; all that is needed is the ability to pass a large electrical current through the region of interest (the resolution is also somewhat limited by the Joule process). This feature clearly sets limits on the types of patterns that can be functionalized, as each of these has to belong to a closed electrical circuit. However, one can imagine more intricate geometrical arrangements, such as lines dotted with nanoscale constrictions, which, when heated, would produce a two-dimensional array of selective absorption spots.