Low-temperature investigation of paramagnetic centres in tetrahedral amorphous carbon deposited by S-bend FCVA

The electron-spin-resonance (ESR) features of tetrahedral amorphous carbon (ta-C) samples deposited by S-bend filtered cathodic vacuum arc (FCVA) are investigated in a wide temperature range (4.3–295 K) before and after post-deposition annealing at 500 C. Special attention is given to the temperature dependence of the linewidths. While the sp3 content does not change with annealing, the temperature trend of the linewidth becomes much smoother for post-deposition annealed samples. The results are discussed in terms of different possible mechanisms of motional line-narrowing and line-narrowing due to hopping motion. 2002 Elsevier Science B.V. All rights reserved. PACS: 81.05.uw; 76.30.-v; 66.35.+