| Popis: |
The identification of atomic defects in solids is of pivotal interest for understanding atomistic processes and solid state properties. Here we report on the exemplary identification of vacancies on each of the two sublattices of SiC by making use of (i) electron irradiation, (ii) measurements of the positron lifetimes, (iii) coincident Doppler broadening studies of the positron-electron annihilation radiation, and (iv) a comparison of the experimental data with theoretical studies. After 0.3 MeV electron irradiation, carbon vacancies ${V}_{\mathrm{C}}$ are identified, where, after 0.5 MeV electron irradiation, predominantly silicon vacancies ${V}_{\mathrm{S}\mathrm{i}}$ are observed. After 2.5 MeV irradiation, divacancies ${V}_{\mathrm{S}\mathrm{i}}\ensuremath{-}{V}_{\mathrm{S}\mathrm{i}}$ are detected. The present results are expected to be of general importance for reliable identification of defects and atomic processes in complex solids. |
