PHOTOELECTRON-SPECTROSCOPY OF THE ANNEALED AND DEUTERIUM-EXPOSED NATURAL DIAMOND (100) SURFACE

Hydrogen, playing a crucial role in diamond film growth, can be desorbed from the diamond (100) surface simply by annealing at elevated temperatures. The effect of such a treatment on the electronic bulk and surface properties of diamond (100) at different temperatures has been investigated by valence band and core level photoelectron spectroscopy. On annealing, additional electronic states appear in the range from 2.5 to 0.5 eV binding energy below the Fermi level. The intensity of those states show an angular dependency. Exposure of the annealed surfaces to atomic deuterium reverses the effect. The data are discussed in the view of models for surface reconstruction. From a thorough comparison of the observed changes in the photoelectron spectra upon annealing with graphite related features we can clearly exclude surface graphitization of the diamond sample in our experiments.