POSITRON AND ELECTRON-SOLID INTERACTIONS

Variable-energy positron beams have been attracting considerable atten tion in recent years as novel probes of surface, thin-film, and interf acial properties in solid systems. The Positron Beam Laboratory at the University of Western Ontario supports research into three separate p rograms. The first involves the study of re-emitted positrons from thi n-films grown on single-crystal substrates under ultra-high vacuum con ditions. The second area of research is the non-destructive depth prof iling of defects in semiconductor materials. This area promises to dom inate positron solid-state research in the near future, as it is rapid ly evolving into a very sensitive quantitative probe of structural poi nt defects. The third area of research is the fundamental study of pos itron and electron scattering and energy loss processes in various sol ids. This program is especially important in gaining a full theoretica l understanding of the positron-solid interaction, which is essential for the application of positron-beam techniques to any area of researc h. In this manuscript, we briefly introduce and review all of these ar eas, with a special emphasis on the fundamental collision results.