ANGLE-RESOLVED X-RAY-PHOTOELECTRON SPECTROSCOPY OF HIGHLY ORIENTED PYROLITIC GRAPHITE

Angle-resolved x-ray-photoelectron-spectroscopy and electron-scattering measurements of cleaved and argon-ion-beam-irradiated highly oriented pyrolitic graphite are reported. It has been found that for the cleaved surface the C 1s photoelectron intensity exhibits strong "photoelectron-diffraction" peaks at angles corresponding to the internuclear directions of nearest- and next-nearest-neighbor atoms in adjacent layers. For the irradiated surface only a broad anisotropic angular distribution was measured, suggesting a randomized near-surface structure. This amorphization is confirmed by complementary electron-energy-loss-spectroscopy and low-energy electron-diffraction measurements.