School of Physics - Research Publications

Permanent URI for this collection

http://hdl.handle.net/11343/309

Filters

2015 - 2016 2
2
Reset filters

Settings
Statistics
Citations
Author: Cervenka, Jiri × Author: Prawer, Steven × End date: 2019 × Start date: 2010 ×

Search Results

Now showing 1 - 2 of 2
  • Item
    Thumbnail Image
    Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition
    Zhan, H ; Garrett, DJ ; Apollo, NV ; Ganesan, K ; Lau, D ; Prawer, S ; Cervenka, J (NATURE PORTFOLIO, 2016-01-25)
    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm(3), were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.
  • Item
    Thumbnail Image
    A graphene field-effect transistor as a molecule-specific probe of DNA nucleobases
    Dontschuk, N ; Stacey, A ; Tadich, A ; Rietwyk, KJ ; Schenk, A ; Edmonds, MT ; Shimoni, O ; Pakes, CI ; Prawer, S ; Cervenka, J (NATURE PUBLISHING GROUP, 2015-03)
    Fast and reliable DNA sequencing is a long-standing target in biomedical research. Recent advances in graphene-based electrical sensors have demonstrated their unprecedented sensitivity to adsorbed molecules, which holds great promise for label-free DNA sequencing technology. To date, the proposed sequencing approaches rely on the ability of graphene electric devices to probe molecular-specific interactions with a graphene surface. Here we experimentally demonstrate the use of graphene field-effect transistors (GFETs) as probes of the presence of a layer of individual DNA nucleobases adsorbed on the graphene surface. We show that GFETs are able to measure distinct coverage-dependent conductance signatures upon adsorption of the four different DNA nucleobases; a result that can be attributed to the formation of an interface dipole field. Comparison between experimental GFET results and synchrotron-based material analysis allowed prediction of the ultimate device sensitivity, and assessment of the feasibility of single nucleobase sensing with graphene.