Photoluminescence spectra of ZnO particles embedded in thin alkali halide crystals

Sample specimens of ZnO particles embedded in thin alkali halide crystals ( KI, KBr and KCl) have been prepared from their melts and photoluminescence spectra have been measured at low temperature. In cases of Ki and KBr matri ces, a bound exciton and a free exciton emission line appear clearly, and i n KCl matrix, the emission lines are very sharp in comparison with the othe r cases. The sharpest lines in KCl matrix are only obtained during the time of a few minutes. The particles are kept in the melt above the melting tem perature. These facts suggest that the use of the alkali halide melt and ra pid solidification of the melt result in a proper etching of the particle s urface. (C) 2000 Elsevier Science B.V. All rights reserved.