Positron annihilation spectroscopy (PAS) has proved to be a powerful tool for the study of defects in solids due to its high sensitivity to the presence of defects such as vacancies, vacancy agglomerates or voids. Furthermore, PAS allows to identify and characterize each of these defects. There are different experimental variations of PAS technique such as positron annihilation lifetime spectroscopy (PALS), which allows to identify and quantify different types of defects and Doppler Broadening that provides information not only about the defects but also on the atomic species that decorate the positrons trapping sites (ie, chemical environments). These experimental techniques coupled with a slow positron beam can be used to study defects profile and subsurface defects in films and coatings. In this paper, we present two examples that demonstrate the potential of PAS for the study of subsurface defects in: i) silica glass implanted with gold ions and ii) high-area nanostructured gold films..
Positron Annihilation Spectroscopy; Films; ion implantation; subsurface defects
