Near-field Microwave Scanning Probe Imaging of Conductivity Inhomogeneities in CVD Graphene
- ORNL
- Asylum Research, Santa Barbara, CA
We have performed near-field scanning microwave microscopy (SMM) of graphene grown by chemical vapor deposition. Due to the use of probe-sample capacitive coupling and a relatively high ac frequency of a few GHz, this scanning probe method allows mapping of local conductivity without a dedicated counter electrode, with a spatial resolution of about 50 nm. Here, the coupling was enabled by atomic layer deposition of alumina on top of graphene, which in turn enabled imaging both large-area films, as well as micron-sized islands, with a dynamic range covering a low sheet resistance of a metal film and a high resistance of highly disordered graphene. The structures of graphene grown on Ni films and Cu foils are explored, and the effects of growth conditions are elucidated. We present a simple general scheme for interpretation of the contrast in the SMM images of our graphene samples and other two-dimensional conductors, which is supported by extensive numerical finite-element modeling. We further demonstrate that combination of the SMM and numerical modeling allows quantitative information about the sheet resistance of graphene to be obtained, paving the pathway for characterization of graphene conductivity with a sub-100 nm special resolution.
- Research Organization:
- Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences
- Sponsoring Organization:
- ORNL LDRD Seed-Money; SC USDOE - Office of Science (SC)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1050361
- Journal Information:
- Nanotechnology, Journal Name: Nanotechnology Journal Issue: 9 Vol. 23; ISSN 0957-4484
- Country of Publication:
- United States
- Language:
- English
Similar Records
Near-field microwave microscopy of high-κ oxides grown on graphene with an organic seeding layer
Integration of Ion Implantation with Scanning ProbeAlignment