Abstract
Zinc oxide, prepared by oxidation of zinc vapor at the temperature above 1500°C, contains metallic zinc or oxygen vacancy. When it isprepared by decomposition of zinc carbonate at the temperature below 500°C, it seems to be stoichiometric. Zinc oxide changed its color, when heated at 1400°C for 3 hours, to yellow with the addition of 1-5 wt% of aluminum oxide, or to brown with gallium oxide. X-ray diffraction analysis shows no peak shift of zinc oxide pattern, while zinc aluminate or zinc gallate was formed, ascertained from their peak positions. The addition of aluminum oxide had the complicated influence upon the optical properties of zinc oxide, while that of gallium oxide causes new absorption band. The results would be explained by the assumption, that color center was formed in zinc oxide and the model of imperfections in zinc oxide containing color center was proposed.
