The surface potential and defects of insulating materials probed by electron and photon emissions

The influence of heat treatments on α-Al₂O₃ samples has been investigated using cathodoluminescence, Auger electron spectroscopy and the SEM mirror method. A significant parameter in charging phenomena is the ability of the material to increase the F ⁺ emission detected from the 330 nm CL band. The sapphire crystal annealed to high temperature (1700°C, 24 hours) may be considered as a stabilized system, including some residual dislocations, with most of the point defects removed and electrically compensated. This is not the case for the polished and not annealed sample which is able to change greatly if the opportunity arises