STUDIES OF DEFECTS IN THE NEAR-SURFACE REGION AND AT INTERFACES USINGLOW-ENERGY POSITRON BEAMS

Positron annihilation spectroscopy (PAS) is a powerful probe to study open-volume defects in solids. Its success is due to the propensity of positrons to seek out low-density regions of a solid, such as vacanci es and voids, and the emissions of gamma rays from their annihilations that carry information about the local electronic environment. The de velopment of low-energy positron beams allows probing of defects to de pths of few microns, and can successfully characterize defects in the near-surface and interface regions of several technologically importan t systems. This review focuses on recent studies conducted on semicond uctor-based systems.