ELECTRICAL AND OPTICAL-PROPERTIES OF AMORPHOUS (SE0.7TE0.3)100-XINX SYSTEM

The effect of In impurity on the dark and photoconductivity and the op tical band gap of amorphous (Se0.7Te0.3)100-xInx has been studied. The activation energy DELTAE and the pre-exponential factor sigma0(0,T) w hich appear in the dc conductivity are found to increase with increasi ng In content. The photocurrent, as a function of illumination intensi ty and time of illumination, has been measured at around room temperat ure. The bimolecular recombination mechanism is found to be predominan t at steady state in all the samples near room temperature. The nonexp onential decay, after stopping the illumination, has been explained in terms of localized-localized recombination. The data have been analyz ed in terms of the dispersive diffusion controlled recombination and m onomolecular recombination is found to be dominant in the transient st ate. The optical band gap is found to decrease with increasing In cont ent. This decrease has been explained on the basis of metallic bonding due to incorporation of In.