Title: Contactless graphene conductance measurements: the effect of device fabrication on terahertz time-domain spectroscopy

Authors: David M.A. Mackenzie; Jonas D. Buron; Peter Bøggild; Peter U. Jepsen; Dirch H. Petersen

Addresses: Department of Micro and Nanotechnology, Technical University of Denmark, Building 345B, 2800 Kgs., Denmark; Center for Nanostructured Graphene (CNG), Technical University of Denmark, 2800 Kgs., Denmark ' Department of Micro and Nanotechnology, Technical University of Denmark, Building 345B, 2800 Kgs., Denmark; Center for Nanostructured Graphene (CNG), Technical University of Denmark, 2800 Kgs., Denmark ' Department of Micro and Nanotechnology, Technical University of Denmark, Building 345B, 2800 Kgs., Denmark; Center for Nanostructured Graphene (CNG), Technical University of Denmark, 2800 Kgs., Denmark ' Department of Photonics, Technical University of Denmark, Building 345A, 2800 Kgs., Denmark ' Department of Micro and Nanotechnology, Technical University of Denmark, Building 345B, 2800 Kgs., Denmark; Center for Nanostructured Graphene (CNG), Technical University of Denmark, 2800 Kgs., Denmark

Abstract: We perform contactless full-wafer maps of the electrical conductance of a 4-inch wafer of single-layer CVD graphene using terahertz time-domain spectroscopy both before and after deposition of metal contacts and fabrication of devices via laser ablation. We find that there is no significant change in the measured conductance of graphene before and after device fabrication. We also show that precise terahertz time-domain spectroscopy can be performed when the beam spot is at sufficient distance (>1.2 mm) from metal contacts.

Keywords: CVD graphene; terahertz time-domain spectroscopy; laser ablation; T-ray; contactless graphene conductance; electrical conductance; metal contacts; nanotechnology.

DOI: 10.1504/IJNT.2016.079660

International Journal of Nanotechnology, 2016 Vol.13 No.8/9, pp.591 - 596

Published online: 07 Oct 2016 *

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