INFLUENCE OF BI2O3 IMPURITIES IN CERAMICS ZNO ON PHOTOACOUSTIC SPECTRA

Photoacoustic (PA) spectroscopy is applied to study the optical absorp tion of ceramic ZnO doped with 1 mol% Bi2O3 sintered at different temp eratures (700-1100 degrees C), PA signal intensities plotted semilogar ithmically reveal two individual regions below 3.0eV (A: 3.0-2.7eV B: 2.6-2.4eV). The steepness factor (slope of exponential optical absorpt ion) obtained at region A decreases with increasing sintering temperat ure, indicating an increase of Bi2O3 segregation at particle surfaces and grain boundaries, The steepness factor at region B increases rapid ly with increasing sintering temperature, indicating an occurrence of structure ordering (decrease of defect states) by the Bi2O3 liquid pha se sintering effect.