Positron annihilation spectroscopy in tomorrow's material defect studies

摘要

Positron Annihilation Spectroscopy (PAS), sometimes refered to as Positron Annihilation Lifetime Spectroscopy (PALS), are non-destructive techniques commonly used for defects and voids study in materials. It provides a handy tool for in-depth profiling down to few microns, and in determining open volume defects like dislocation, agglomerates, and vacancies at ppm concentration. PAS with the aid of Doppler broadening has certainly opened a new gateway in the spectroscopy of solid state physics, metals, RO systems, and semiconductors. Since it is an antiparticle of the electron it gives better information on the electron density in the material of interest. The lifetime of a positron is a complex function of electron density present at the annihilation site. To add beauty, in principle PAS gives the type and concentration of the defect independently by a single measurement. This article presents PAS based on the most relevant, most iconic, and most recent references.