Nanowire
A nanowire ( English nanowire ) is a fine, elongated piece of metal , semi-metal or compound semiconductor having a diameter in the range up to 100 nanometers (0.1 micrometers = 0.0001 mm ). Metallically conductive carbon nanotubes can also be referred to as nanowire in the sense of an electrical conductor. As a (microbial) nanowires also electrically conductive cell appendages of are bacteria called that help the organisms external electron acceptors use.
Manufacturing
A method that is frequently used in research for the production of embedded or free nanowires is the electrochemical deposition of the desired metal in suitable nanopores and subsequent removal. For example, the pores of aluminum oxide , which can be dissolved with strong bases or with hydrofluoric acid , are suitable .
Another method that is frequently used is direct growth in a vapor-liquid-solid process . This can be used both for growth on a substrate and for the production of loose nanowires, which are sucked off with the gas flow through the reactor. The diameter of the nanowires produced in this way depends on the size of the catalyst droplets used. The production of metal droplets in the nanometer range is difficult because they are not thermodynamically stable.
In semiconductor technology , nanowires are produced using lithographic processes , which in this case are particularly complex because the desired structures are smaller than the wavelength of visible light . Special processes must therefore be used and short-wave light such as UV light must be used (for example laser light with a wavelength of 193 nm). Chips with a conductor track width of 32 nm can now be produced (as of 2011).
New research also deals with the production of nanowires based on DNA . In this process, DNA strands are metallized to increase conductivity. During the metallization with, for example, silver particles, neighboring strands are simultaneously crosslinked. In a second metallization process, gold can be deposited on the silver particles from a solution. The diameter of the nanowires can be varied over the duration of the gold deposition. With the new method, micrometer-long, electrically contactable nanowires are obtained that have the potential for the production of miniaturized circuits .
Individual evidence
- ↑ Jiangtao Hu, Teri Wang Odom, Charles M. Lieber: Chemistry and Physics in One Dimension: Synthesis and Properties of Nanowires and Nanotubes . In: Accounts of chemical research . 32, No. 5, 1999, pp. 435-445.
- ↑ Jan Timper, Katrin Gutsmiedl, Christian Wirges, Janine Broda, Michael Noyong, Joachim Mayer, Thomas Carell, Ulrich Simon: Production of conductive nanostructures by surface click reaction and controlled metallization of DNA . In: Angewandte Chemie . 2012, doi : 10.1002 / anie.201202401 (communication in print).