Cathodoluminescence of zinc oxide crystals grown from melt under high pressure in the presence of ytterbium oxide

A mixture of poly- and single crystals of zinc and ytterbium (2 at.%) oxides have been grown from the melt at high temperature (1430°C) and high pressure (3.8 GPa). The crystals were transparent under examination with naked eye. The diameter of crystals was in the range from 0.005 to 2 mm. X-ray diffraction confirmed presence of individual zinc and ytterbium oxides in the recovered samples. No change of zinc oxide lattice parameters was observed compared to pristine zinc oxide. Cathodoluminescence spectra of the mixture were recorded at 77 and 293 K. The collected spectra exhibit UV, green and near-infrared bands due to exciton recombination, presence of oxygen vacancies and ytterbium ions in ZnO crystals, respectively.