Raman and ellipsometry spectroscopic analysis of graphene films grown directly on Si substrate via CVD technique for estimating the graphene atomic planes number

•Graphene films with various thicknesses were grown directly on Si substrates.•The number of graphene atomic planes is determined by Raman scattering intensity.•The number of atomic planes of graphene was determined by ellipsometry amplitude.•The number is correlated with AFM and showed resolution of 0.36 nm/graphene layer.

Two reliable approaches for estimating the number of atomic planes of graphene films grown on Si substrate were demonstrated by Raman and ellipsometry spectroscopies. The first approach depends on the measurement of the ratio of the integrated Raman scattering intensity of the graphene G band to the optical phonon band of Si substrate (IG/ISi). The second approach belongs to ellipsometry measurement of the ratio of the amplitude of the reflected polarized light from the surface of the graphene films to the amplitude of reflected polarized light from the surface of the Si substrate (ΨG/ΨSi). These two approaches could efficiently recognize the number of atomic planes in the graphene films (1 ≤ n ≤ 10). The results were compared with atomic force microscopy (AFM) measurement and showed a linear regression with slope of 0.36 ± 0.01 nm/graphene layer. The Two approaches will open a new avenue to efficiently count the number of graphene layers during the preparation process.

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