We demonstrate two-dimensional mapping of current flow in graphene devices by using a single-spin scanning magnetometer based on a nitrogen-vacancy defect center in diamond. We first image the stray magnetic field generated by the current and then reconstruct the current density map from the field data. We focus on the visualization of current flow around a small sized current source of ∼500 nm diameter, which works as an effective point contact. In this paper, we study two types of point-contacted graphene devices and find that the overall current profiles agree with the expected behavior of electron flow in the diffusive transport regime. This work could offer a route to explore interesting carrier dynamics of graphene including ballistic and hydrodynamic transport regimes.
Bibliographical noteFunding Information:
This work was funded by Defense Agency for Technology and Quality (DTaQ), Korea, and the MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center) support program (No. IITP-2020-0-01606) supervised by the IITP (Institute of Information and Communications Technology Planning and Evaluation). S.J., W.J., and G.-H.L. were supported by the Samsung Science and Technology Foundation (Project No. SSTF-BA1702-05) and the National Research Foundation of Korea (NRF) funded by the Korean Government (Grant No. 2016R1A5A1008184). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, Grant No. JPMXP0112101001, JSPS KAKENHI Grant No. JP20H00354, and the CREST (No. JPMJCR15F3), JST. H.-G.P. acknowledges support from the Samsung Research Funding and Incubation Center of Samsung Electronics (No. SRFC-MA2001-01).
© 2021 Author(s).
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)