Defects in nonstoichiometric TiC studied by TDS

Implantation and trapping effects of helium and neon are studied by thermal desorption spectrometry (TDS) in single-crystalline Ti1C0.924, which has a structural defect concentration on the order of percents on the carbon sublattice. For neon a first-order surface-related release peak and a very broad diffusional bulk-related release peak are found. For helium only the bulk peak has significant magnitude. The bulk diffusion mechanism can be explained by either a hopping or a vacancy assisted mechanism. In addition, neon is capable of displacing titanium atoms, and hence of creating vacancy clusters which have a stronger binding energy for neon than the structural defects; this is clearly visible in the spectra. (orig.)