Sample preparation and photoluminescence of ZnO particles embedded in thinalkali halide crystals

We have prepared samples of ZnO particles embedded in thin alkali halide cr ystals by a melt growth method and have measured photoluminescence spectra at various temperatures. In the spectra measured at 8.5 K, free exciton (FE ) and bound exciton (BE) emission lines are clearly recognized, while the w ell-known green band is hardly observed. The FE line appears at temperature s between 8.5 K and 300 K. The widths of both lines are very sharp and almo st equal to that of ZnO epitaxial layers grown by a molecular beam epitaxy method. These results strongly suggest that high-quality ZnO particles can be well embedded in thin alkali halide crystals.