Effect of annealing on cathodoluminescence of synthetic zincite single crystals

We have studied the effect of annealing on the luminescent properties of zincite single crystals grown from hydrothermal solutions. Annealing in the temperature range of 400–700°C increases the edge cathodoluminescence (CL) intensity in zincite. At the same time, raising the annealing temperature from 800 to 1100°C leads to quenching of the edge emission and increases the intensity of the green band. In addition, annealing leads to broadening of the edge luminescence band and shifts it to lower energies. In contrast, annealing shifts the impurity band to higher energies. The observed changes in the CL behavior of zincite are tentatively interpreted in terms of the temperature effect on the concentration of structural defects, in particular, oxygen vacancies and their complexes.