Photopyroelectric Spectrum of MNO2 Doped Bi2O3 - TiO2 - ZnO Ceramic Combination

Photopyroelectric spectroscopy is used to study the energy band-gap of the ceramic (zno + 0.25 bi2o3 +0.25 tio2 + x mno2 ) , x = 0 - 1.3 mol%, sintered at isothermal temperature 1190 and 1270°c for 2 hours in air. the wavelength of incident light, modulated at 9 hz, is kept in the range of 300 to 800 nm and the photopyroelectric spectrum with reference to the doping level is discussed. the energy band-gap is estimated from the plot (phv)2vs hv and is 2.80 ev for the samples without mno2 at both sintering temperatures. it decreases to 2.08 ev with a further increase of mn02 • the phase constitution is determined by xrd analysis. microstructure and compositional analysis of the selected areas are analyzed using sem and edx. the maximum relative density, 91.4 %, and the grain size, 47 μm, were observed in this ceramics combination.