Characterization of defects in as-grown CVD diamond films and HPHT diamond powders by electron paramagnetic resonance

Several defect centers, labeled as KUL1-7, have been detected by electron paramagnetic resonance in CVD diamond films and synthetic diamond powders. Their g values were determined relatively to the PI (N-s(0)) center, for which the value of g = 2.00216(1) with anisotropy g(parallel to)-g(perpendicular to) < 0.00003 was determined. Analysis of the hyperfine interaction structure reveals the presence of the following impurities: one hydrogen atom in the centers KUL2-4, one nitrogen atom in the KUL5 and one Mn atom in the KUL7 center. The centers KUL1, 3-6 were observed exclusively in CVD films, KUL7 could only be detected in HPHT powders grown with a Mn-Ni catalyst, while the KUL2 center was found both in CVD and HPHT diamond. Microscopic models for some of the observed centers are discussed.