| AVS 55th International Symposium & Exhibition | |
| Graphene Topical Conference | Tuesday Sessions |
| Session GR+TF+NC-TuA |
| Session: | Graphene: Characterization, Properties, and Application |
| Presenter: | K. Leifer, Uppsala University, Sweden |
| Authors: | S.H.M. Jafri, Uppsala University, Sweden T. Blom, Uppsala University, Sweden E. Widenqvist, Uppsala University, Sweden K. Carva, Uppsala University, Sweden B. Sanyal, Uppsala University, Sweden O. Eriksson, Uppsala University, Sweden H. Grennberg, Uppsala University, Sweden U. Jansson, Uppsala University, Sweden R.A. Quinlan, College of William and Mary B.C. Holloway, Luna Innovations Incorporated A. Surpi, Uppsala University, Sweden K. Leifer, Uppsala University, Sweden |
| Correspondent: | Click to Email |
Due to their large surface areas, the conductivity of graphene and carbon nano-sheets depends strongly on their chemical environment. This is the base for future environmental sensors containing graphene sheets. Here, ab-initio calculations propose a possibility of conductivity increase. In the experiment, a 1-2 orders of magnitude increase of the conductivity is observed experimentally on sub-nanometre carbon nano-sheets by using an in-situ nano-manipulation set-up. The conductivity of the graphene sheets was assessed from first-principle simulations. Insertion of defects in the graphene sheets can lead to a strong increase of the conductivity of single graphene sheets. To study this result experimentally, we carried out conductivity measurements on sub-nanometre graphene nano-sheets that are deposited on W-substrates by radio-frequency plasma-enhanced chemical vapour deposition. This deposition process creates free-standing micrometer-sized carbon nano-sheets with sub-nanometre thickness. These nano-sheets were exposed to an acid treatment. It has been shown recently that such acid treatment creates defects in these sheets. Using a nano-manipulator inside a scanning electron microscope, we individually contacted the nano-sheets and measured their resistance as a function of their functionalization. From more than 1000 measurements we obtain a 1-2 order of magnitude increase of conductivity in the functionalised carbon nano-sheets as compared to just water treated or untreated carbon nano-sheets. This result corresponds well to the conductivity change obtained from theory. This study makes it possible to create environmental sensors based on graphene like carbon nano-sheets.