Thickness Dependent Interlayer Magnetoresistance in Multilayer Graphene Stacks

Figure 1

Typical Raman spectra of as-grown MLG (taken from the top surface, i.e., from the “defect-free region”) with nominal thicknesses of (a) ~60 nm (batch S1), (b) ~200 nm (batch S2), and (c) ~300 nm (batch S3). (d) Typical Raman spectrum taken from the layers at the MLG/Ni interface (“defective region”). As seen from Figures (a)–(c), defect () peak at 1350 cm⁻¹ is absent in all these cases. The bottom insets in these figures show a 10x magnified view of the spectrum close to 1350 cm⁻¹ range, and still no defect peak can be discerned above the noise level. The Raman band of each batch is symmetric and can be fitted with a single Lorentzian as shown in the top insets of Figures (a), (b), and (c). These Raman features are valid for almost all areas of the samples. In Figure (d) strong peak is observed from the transferred MLG sample, taken from the bottom surface (after removing the Ni and flipping over the MLG stack). This confirms the defective nature of the interfacial layers.

(a)

(b)

(c)

(d)