UK scientists demonstrate ultra-sensitive graphene-based gas sensor
Article Type: News From: Sensor Review, Volume 28, Issue 4
In 2004, a team of scientists at Manchester University (UK) discovered graphene, a single atom-thick form of carbon with a hexagonal, gauze-like structure. This has since attracted huge interest from the materials science,nanotechnology and solid-state physics communities and now the same team has shown that it is exceedingly sensitive to gases. Researchers from the Manchester Centre for Mesoscience and Nanotechnology, together with colleagues from the Institute for Microelectronics Technology in Russia and the Institute for Molecules and Materials at the University of Nijmegen, Netherlands, reported their findings in a paper published in Nature Materials.
Gas molecules interact with graphene by attaching themselves to the surface of the structure without disrupting it but in so doing either add or remove electrons. This leads to a significant chance in the material’s conductance which was observed as individual molecules of compounds such as carbon monoxide(CO) and nitrogen dioxide (NO2) interacted with the graphene film. The researchers created micron-sized flakes of graphene by micromechanical cleavage of graphite at the surface of oxidised silicon wafers and then used electron beam lithography to make electrical contacts. A single flake, around 10 μm across, was placed in a chamber and its electrical resistance measured as NO2 was slowly added. They observed distinct and discrete step-changes in resistance, corresponding to single molecules of the gas adsorbing to and desorbing from the graphene flake. According to the researchers, this level of sensitivity is typically millions of times higher than that of any other gas detector previously demonstrated and reaches the theoretical limit – single molecule detection. They argue that graphene-based gas sensors could be produced commercially from epitaxial graphene wafers which are now being grown in many laboratories around the world. Applications could include high sensitivity CO sensors and detecting illicit substance hidden in luggage but further work will be needed to achieve selectivity and minimise the influence of water vapour.
For further details please contact: Dr Kostya Novoselov, Tel.:+44-(0)161-275-4119, e-mail: kostya@manchester.ac.uk
Rob Bogue
Reference
Schedin, F., Geim, A.K., Morozov, S.V., Hill, E.W., Blake, P., Katsnelson,M.I. and Novoselov, K.S. (2007), “Detection of individual gas molecules adsorbed on graphene”. Nature Materials, Vol. 6, pp. 652-5.
