The X-band ESR of thin diamond films deposited from a mixture of 99.5% ${\mathrm{H}}_2$ and 0.5% ${\mathrm{CH}}_4$ is compared to those of films similarly prepared from ${\mathrm{D}}_2$-${\mathrm{CD}}_4$ and ${\mathrm{H}}_2$${\mathrm{-}}^{13}$${\mathrm{CH}}_4$ mixtures. The main line and the satellites at ±7.2 G are unaffected by annealing at T≤1100 °C, but their intensity is reduced upon annealing at ∼1500 °C. Since the satellites are absent from the deuterated films, they are attributed to newly identified dangling-bond H centers, possibly on internal surfaces, but more plausibly embedded in the bulk. This is consistent with the ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ relaxation rate, which indicates a uniform distribution of paramagnetic centers.

• Received 24 August 1993

DOI:https://doi.org/10.1103/PhysRevB.48.17595