The electronic states of H defects in the sub-surface were investigated by using the ab initio pseudopotential method. It was found that a deep level and a shallow level near to the valence band maximum in the energy band-gap were generated by a H atom and H complex defects in the sub-surface, respectively. The H complexes in the sub-surface were found to be stable under a perfectly hydrogenated surface. The results provided a theoretical background for the experimental observations and the model for p-type surface conduction.

Ab initio Study on the Electronic States of Hydrogen Defects in Diamond Sub-Surfaces. C.Kanai, K.Watanabe, Y.Takakuwa: Japanese Journal of Applied Physics-1, 2003, 42[6A], 3510-3