Local electrical imaging using microwave impedance microscope is performed on graphene in different modalities, yielding a rich hierarchy of the local conductivity. The low-conductivity graphite oxide and its derivatives show significant electronic inhomogeneity. For the conductive chemical graphene, the residual defects lead to a systematic reduction of the microwave signals. In contrast, the signals on pristine graphene agree well with a lumped-element circuit model. The local impedance information can also be used to verify the electrical contact between overlapped graphene pieces. © 2009 American Chemical Society.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-F1-033-02
Acknowledgements: We thank K. Todd for the assistance with pristine graphene, D. Goldhaber-Gordon for useful discussions, and C. Buenviaje-Conggins for the instrumental advice. The research is supported by Center of Probing the Nanoscale (CPN), Stanford University, gift grants from Agilent Technologies, Inc., and DOE Contract DE-FG03-01ER45929-A001. This publication is also based on work supported by Award No. KUS-F1-033-02, made by King Abdullah University of Science and Technology (KAUST) under the global research partnership (GRP) program. CPN is an NSF NSEC, NSF Grant No. PHY-0425897. The work on graphene synthesis is supported by MARCO-MSD, Intel, and ONR.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.