X-ray diffraction of multi-layer graphenes: Instant measurement and determination of the number of layers

A method for determining the number of layers (NL) or thickness (DGP) of multi-layer graphene (MLG) using X-ray diffraction (XRD) is reported for the first time. The XRD pattern showed clear variations in the full-width-at-half-maximum (FWHM) values of the (0 0 2) peak of crystalline MLG with NL = 3, 4, 5, 6, and 7. The large FWHM difference per layer and the instant measurement of large areas of MLG demonstrates that XRD is a powerful probe. The obtained linear plot of FWHM versus 1/DGP and the NL-dependent evolution of the interlayer distance (d002) toward the d002 of graphite are also discussed.