Structure and anomalous light scattering of Er-doped transparent glass-ceramics containing ZnO nanocrystals

Potassium zinc aluminosilicate glass doped with 1.5 mol% Er2O3 was subjected to successive heat treatments at 720 and 750 degrees C resulted in precipitation of ZnO nanocrystals. After each hold, the volume fraction and size of crystals in transparent glass-ceramics were determined, and optical density spectrum was recorded. Analysis of optical spectra revealed that: the surrounding of Er3+ ions differs in the initial glass and glass-ceramics; a strong absorption band is observed in glass-ceramics at wavelengths longer than 1000 nm, which is caused by localized surface plasmon resonance in semiconducting ZnO nanocrystals; the so-called "anomalous light scattering" is observed, i.e., scattering coefficient of glass-ceramics in the spectral range 480-800 nm is a power function of the inverse wavelength, and the exponent ("the scattering exponent") is appreciably greater than the Rayleigh value 4. The experimental scattering coefficient of one glass-ceramic is compared with that calculated for the model proposed earlier.