Abstract
Chemical vapor deposition (CVD) grown graphene used in (scanning) transmission electron microscopy [(S)TEM] studies must undergo a careful transfer of the one-atom-thick membrane from the growth surface (typically a Cu foil) to the TEM grid. During this transfer process, the graphene invariably becomes contaminated with foreign materials. This contamination proves to be very problematic in the (S)TEM because often >95% of the graphene is obscured, and imaging of the pristine areas results in e-beam-induced hydrocarbon deposition which further acts to obscure the desired imaging area. In this article, the authors examine two cleaning techniques for CVD grown graphene that mitigate both aspects of the contamination problem: visible contamination covering the graphene, and "invisible" contamination that deposits onto the graphene under e-beam irradiation. The visible contamination may be removed quickly by a rapid thermal annealing to 1200 °C in situ and the invisible e-beam-deposited contamination may be removed through an Ar/O2 annealing procedure prior to imaging in the (S)TEM.
| Original language | English |
|---|---|
| Article number | 011801 |
| Journal | Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics |
| Volume | 36 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2018 |
Funding
The authors would like to thank Ivan Vlassiouk for the provision of the graphene samples and Francois Amet for performing the argon-oxygen cleaning procedure. This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility (S.V.K.) and was supported by the Laboratory Directed Research and Development Program of the Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. DOE (O.D., S.K., S.J.).
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| Office of Science | |
| Oak Ridge National Laboratory |