The surface and bulk core lines in crystalline and disordered polycrystalline graphite

Attempts have been made recently to reveal surface-bulk core-level splitting in graphite using high resolution synchrotron radiation or X-ray photoelectron spectra. However, the different author descriptions of the carbon 1s line-shape in terms of two Doniach-Sunjic (DS) components still show discrepancies. In this work, we present high resolution, high quality carbon 1s X-ray photoelectron spectra and peak fitting results, and compare them with previous works. The relative intensity of the bulk and surface components varied with changes to the photoelectron takeoff angle. Here, we interpret carbon 1s line-shape in highly oriented pyrolytic and disordered polycrystalline graphite, taking into account perturbations to the pure DS line-shape and the effect of tilt on the binding energies of the two components. The results explain the apparent disagreement among published works.