Hydrogen is introduced in polycrystalline diamond during the deposition process (intrinsic hydrogen) or by post-hydrogenation and bulk diffusion. It is possible to control in a selective manner (by chemical or thermal treatments) the removal of superficial or subsurface hydrogen. The photoelectron spectroscopy (XPS and UPS) results at the moderately doped polycrystalline diamond surface are reported, depending on hydrogenation or dehydrogenation treatments. The Fermi level pinning position shift and the oxygen bonding are deduced from XPS spectra. The modification of the valence band is followed by UPS.
