Hydrogen passivation of electrically active defects in diamond

Subjecting natural diamond single crystals to the action of atomic hydrogen in a hydrogen plasma is shown to result in the passivation of interband states in the crystal resulting in a marked reduction in the resistivity to about 105 Ω cm from the expected high resistivity of∼1016 Ω cm. When the hydrogenated crystals are heat treated in a neutral ambient, the hydrogen can be expelled from the crystals, restoring the high resistivity. The behavior of natural diamond crystals, with respect to the effects of hydrogen, is shown to be similar to the behavior of diamond thin films synthesized by plasma-enhanced chemical vapor deposition techniques.