| AVS 65th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Monday Sessions |
| Session 2D+MI+NS-MoA |
| Session: | 2D Materials Characterization including Microscopy and Spectroscopy |
| Presenter: | Sebastian Funke, Accurion GmbH, Germany |
| Authors: | S. Funke, Accurion GmbH, Germany P. Braueniger-Weimer, University of Cambridge, UK S. Hofmann, University of Cambridge, UK P.H. Thiesen, Accurion GmbH, Germany |
| Correspondent: | Click to Email |
By combining the resolution of optical microscopy and the sensitivity of thin films, imaging ellipsometry (IE) is a powerful tool to characterize thin materials. It allows to measure monolayers of 2D-materials but also to visualize these monolayers on arbitrary substrates. It overcomes the need of specially tuned SiO2 thicknesses to visualize e.g. Graphene in an optical microscope.
In the talk we present [1], the characterization of Graphene throughout all stages of the manufacturing process from the growth on Cu-foil up to the transferred sample on Si wafers. Unlike other methods IE directly visualizes graphene on the rough Cu. We apply IE to resolve a large area map of Graphene on Cu. The Graphene is directly characterized on the Cu-foil, no oxidation of the Cu is needed. To overcome the waviness of the foil, an autofocus algorithm is developed and applied.
IE is also able to distinguish a Graphene monolayer and hBN monolayer after the transfer process to a Si/SiO2 substrate. We show large area map of the transfered sample. The contrast mode of IE is able to distinguish the different regions: (a) substrate only, (b) hBN only, (c) Graphene only and (d) an overlapping region of hBN and Graphene. The complete sample approx. 1cm x 0.8 cm is recorded in less than 6 minutes and shows defects and wrapping of hBN of a size as small as 4 µm.
Lastly, we apply IE to characterise full 4’’ wafers of graphene on Si.
[1] Braueniger, Funke et al. submitted