Direct Writing of Conductive Regions in Graphene Oxide via Focused Ion Beam (FIB) Irradiation

Transcription

1 Direct Writing of Conductive Regions in Graphene Oxide via Focused Ion Beam (FIB) Irradiation By: Derrek E. Lobo, Monash University, Victoria, Australia Supervisor: Dr Mainak Majumder

2 Motivation of graphitic materials FIB irradiation as a reduction method for graphene oxide Planar capacitors Current progress

3 Good material stability and strength High electronic mobility hence high conductivity Spatial patterning opens up many applications in nano-electronics Specifically the fabrication of planar microsupercapacitors A. K. Geim, K. S. Novoselov, The rise of graphene. Nat Mater 6, 183 (2007). Ohta, T.; Bostwick, A.; Seyller, T.; Horn, K.; Rotenberg, E. Controlling the electronic structure of bilayer graphene. Science 2006, 313, Son, Y.; Cohen, M. L.; Louie, S. G. Energy gaps in graphene nanoribbons. Phys. Rev. Lett. 2006, 97,

4 Mechanical exfoliation Wet chemical synthesis Epitaxial growth Chemical vapour deposition (CVD) Arc discharge

5 Westervelt, R.M., Graphene Nanoelectronics. Science, (5874): p Bell, D.C., et al., Precision cutting and patterning of graphene with helium ions. Nanotechnology, (45): p Dimiev, A., et al., Layer-by-Layer Removal of Graphene for Device. Science, (6021): p

6 Wang, Q.H. and M.C. Hersam, Characterization and nanopatterning of organically functionalized graphene with ultrahigh vacuum scanning tunneling microscopy. MRS Bulletin, (07): p Byun, I.-S., et al., Nanoscale Lithography on Monolayer Graphene Using Hydrogenation and Oxidation. ACS Nano, (8): p

7 Graphene oxide is made up of a sp 2 bonded carbon lattice work with oxygen functionalities attached. These functionalities give it interesting chemical properties with the possibility of grafting additional groups to them. Reduction of GO leads to interesting electrical properties as well (GO is insulating while rgo is conductive) in fact it is 5 orders of magnitude more conductive than GO. Gao, W., et al., New insights into the structure and reduction of graphite oxide. Nat Chem, (5): p Stankovich, S., et al., Synthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide. Carbon, (7): p Zhu, Y., et al., Graphene and Graphene Oxide: Synthesis, Properties, and Applications. Advanced Materials, (35): p

8 Y. Zhang et al., Direct imprinting of microcircuits on graphene oxides film by femtosecond laser reduction. Nano Today 5, 15 (2010). Wei, Z., et al., Nanoscale Tunable Reduction of Graphene Oxide for Graphene Electronics. Science, (5984): p

9 Benefits : Small feature size Tuneable amount of reduction Complex patterning possible Hypothesis(conservation of momentum) Ga ions are incident on the GO substrate with a certain amount of momentum this leads to deformation on the c-c and c-o bonding structure. Since the c-o bonding is weaker these are more likely to be effected and broken leading to a reduction of the GO substrate.

10 D. E. Lobo, J. Fu, T. Gengenbach, M. Majumder, Localized Deoxygenation and Direct of Graphene Oxide Films by Focused Ion Beams. Langmuir 28, (2012/10/16, 2012).

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12 D. E. Lobo, J. Fu, T. Gengenbach, M. Majumder, Localized Deoxygenation and Direct of Graphene Oxide Films by Focused Ion Beams. Langmuir 28, (2012/10/16, 2012).

13 Specific capacitance: 2.50 mf/cm 2 Energy density: 9.03 x 10-7 Wh/cm 2 Power density: 3.57 x 10-3 W/cm 2 Electrolyte: 1M Na 2 SO 4 Gao, W., et al. (2011). "Direct laser writing of micro-supercapacitors on hydrated graphite oxide films." Nat Nano 6(8):

14 Specific capacitance: 2.32 mf/cm 2 Energy density: 1.60 x 10-6 Wh/cm 2 Power density: 1.07 x 10-1 W/cm 2 Ionic liquid: 1-butyl-3-methylimidazolium bis(trifluoromethylsulfony)imide with fumed silica nanopowder El-Kady, M. F. and R. B. Kaner (2013). "Scalable fabrication of high-power graphene micro-supercapacitors for flexible and on-chip energy storage." Nat Commun 4: 1475.

15 Summary We provide a novel way to directly pattern rgo regions on a GO film. There exists two clear regimes one of preferential reduction and one of preferential amorphisation. The feature sizes can range from 15nm to 100µm. Shows good potential as a method for the fabrication of all carbon planar capacitors.

16 Dr Mainak Majumder Dr Jing Fu Dr Thomas Gengenbach Acknowledgements My Lab mates Parama Banerjeea, Phillip Sheath, Rachel Tkacz, Sam Martin and Mahdokht Emadishaibani

17 Thank you Questions?