COMPARATIVE-STUDY OF PHOTOCONDUCTIVITY IN MIXED LATTICES OF PBCRO4-HGO-ZNO

Comparative study of photoconductivity in mixed lattices taking PbCrO4 as one of the components, i.e. PbCrO4-ZnO, PbCrO4-HgO and PbCrO4-HgO- ZnO have been carried out. Comparative dependence of photocurrent on v arious parameters such as intensity of illumination, time, temperature , etc. has been studied. Photocurrent is found to vary sublinearly for all compositions except for 75% PbCrO4-25% HgO composition. Sublinear dependence of photocurrent on intensity of illumination confirms the existence of an exponential trap distribution near to the conduction b and. The photocurrent versus excitation intensity relationship changes from superlinear to sublinear nature for 75% PbCrO4-25% HgO compositi on. Thermal quenching of dark current and photocurrent indicates the p resence of sensitising centres near to the valence band. The locations of Fermi-levels corresponding to different temperature regions have b een calculated out for all compositions.