Chemical vapour deposition diamond studied by optical and electron spin resonance techniques

This work discusses the current situation in the study of bulk defects in diamond, grown by chemical vapour deposition (CVD), using optical absorption, luminescence, and electron spin resonance techniques. CVD diamond appears distinct from other types of diamond in that it exhibits significant concentrations of bulk defects involving hydrogen, silicon, and possibly tungsten impurities. Importantly, as regards doping, p-type conductivity up to the degeneracy level can be achieved by boron incorporation, while n-type conductivity can be realized by phosphorus doping. A generally observed trend is cross fertilization between the studies of various types of diamond: the knowledge of the properties of intrinsic and irradiation-induced defects, obtained from extensive studies of natural and high-pressure synthetic diamond crystals, helps in understanding the presence of certain radiation-damage-related centres in as-grown CVD films. In return, some achievements from the study of defect centres in CVD diamond may provide useful information for modelling of defects in crystalline diamond and other semiconducting materials.