Spatially resolved cathodoluminescence investigations on zinc oxide ceramics

Abstract

By using the spatially resolved Cathodoluminescence (CL) measurement technique in a scanning electron microscope, it is found, that pure ZnO ceramics and varistor active ceramics with Bi2O3 as a single additive have different luminescence properties. The influence of pre‐treatment and excitation conditions on the grain boundary contrast is studied. In consideration of the fact, that the intensity and the spectral composition of the Cathodoluminescence are interconnected with the defect structure and the local conductivity, it is concluded, that Bi2O3 changes the concentration and distribution of the native defects. The experimental results indicate, that the height of the potential barriers at the grain boundaries decreases after annealing under reducing conditions.