Characterization of heterogeneity of CVD graphene on copper foil by scanning probe microscopy and Raman spectroscopy

Abstract

The comparative analysis of the structural, morphological, and local electrical properties of CVD graphene films synthesized at atmospheric and low pressure CVD growth conditions was carried out. The use of electrical techniques of scanning probe microscopy, such as Kelvin probe force microscopy, scanning capacitance microscopy, electrostatic force microscopy, and conductive atomic-force microscopy for investigation of heterogeneous graphene coverage was discussed. A significant change in the surface potential values was observed indicating the formation of p-type multilayered graphene domains on single layer graphene at low pressure and n-type multilayered graphene films at atmospheric pressure CVD. The effect of Ar flow rate increasing during cooling stage in the temperature range of 700–200 °C causing graphite formation was described. The employment of surface potential spectroscopy allows to indicate the presence of nonlinear phenomena in heterogeneous graphene.

Keywords:

• CVD graphene
• Raman spectra
• Kelvin probe force microscopy
• scanning capacitance microscopy
• surface potential

Acknowledgments

The SPM studies were carried out at the Center of Collective Use “Testing Center for Nanotechnologies and Advanced Materials” of the Mikheev Institute of Metal Physics, UB of RAS. The re-equipment and comprehensive development of the “Geoanalitik” shared research facilities of the IGG UB RAS is supported by the grant of the Ministry of Science and Higher Education of the Russian Federation (Agreement No. 075-15-2021-680).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation [theme “Spin” No. 122021000036-3, theme “Function,” No. 122021000035-6]. Raman measurements were carried out within the Common Use Center “Geoanalitik” of IGG UB of RAS state budget theme No. 123011800012-9.