Conduction mechanism in amorphous Se75In25−xPbx films

Conductivity measurements were made on thin amorphous films of Se75In25−xPbx (where x=0, 4, 6, 10) in the temperature range of 200–400 K. The conduction in the low-temperature region is found to be due to variable range hopping, while that in the high-temperature region is due to thermally assisted tunneling of the carriers in the localized states near the band edge. The effect of the addition of Pb to Se–In alloys is to reduce the density of states near the Fermi level. For any given composition the density of states near the Fermi level decreases with increasing Pb concentration. These results were analyzed in terms of the Davis–Mott model.