Abstract
Carbon films were prepared using a filtered cathodic vacuum arc deposition systemoperated with a substrate bias varying linearly with time during growth. Ionenergies were in the range between 95 and 620 eV. Alternating dark, high density (sp3 rich) bands andlight, low density (sp2 rich) bands were observed using cross-sectional transmission electron microscopy,corresponding to abrupt transitions between materials with densities of approximately 3.1 and2.6 g cm−3. No intermediate densities were observed in the samples. The low density bands showstrong preferred orientation with graphitic sheets aligned normal to the film. Afterannealing, the low density bands became more oriented and the thinner high density layerswere converted to low density material. In molecular dynamics modelling of film growth,temperature activated structural rearrangements occurring over long timescales ( ps) caused the transition from sp3 rich to oriented sp2 rich structure. Once this oriented growth was initiated, the sputtering yield decreased andchannelling was observed. However, we conclude that sputtering and channelling events,while they occur, are not the cause of the transition to the oriented structure.
Published Version
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