X-RAY PHOTOELECTRON-SPECTROSCOPY ANALYSIS OF PLASMA-TREATED SURFACES OF DIAMOND FILMS

The surface band bending of polycrystalline diamond films treated with O-2 or H-2 plasma has been investigated by means of X-ray photoelectron spectroscopy. A shift in the binding energy in the carbon 1s core level spectrum is observed depending on the plasma treatment. The surface Fermi level moves away from the valence band edge by O-2 plasma treatment, while it comes close to the valence band edge by H-2 plasma treatment. The energy difference between the surface Fermi level positions of the O-2- and H-2-plasma-treated samples is estimated to be about 0.7 eV. It is also observed that the surface Fermi level of the Ar-sputtered sample is located closer to the valence band edge than that of the H-2-plasma treated sample.