Chemical erosion of atomically dispersed doped hydrocarbon layers by deuterium

The chemical erosion of atomically dispersed Ti-doped (∼10 at.%) amorphous hydrocarbon layers (a-C:H:Ti) was investigated in the temperature range of 300–800 K for 30 eV deuterium impact. Compared to pyrolytic graphite, the methane production yield is strongly reduced at elevated temperatures. This reduction starts from temperatures just above room temperature and is even larger than for B-doped graphite. The reduction of the activation energy for hydrogen release may be the dominant interpretation for the decreased hydrocarbon formation. The ratio of emitted CD3 to CD4 increases with temperature for pyrolytic graphite and even stronger for the doped layers. The fluence dependence of the chemical erosion yield was determined, which is explained by enrichment of the dopant due to the preferential erosion of C.