Electrical transport mechanism in Cd5Se95-xZnx chalcogenide thin films

The thin films of Cd5Se95-xZnx (x = 0, 2, 4, 6) chalcogenide semiconductors were deposited by using thermal coating unit on ultra clean glass substrate under a high vacuum of 10(-6) Torr. The amorphous structure of the deposited films has been confirmed by X-ray diffraction technique. Current-voltage (I-V) measurements at high electric fields have been carried out at different fixed temperature for the present samples. The analysis of the data could be fitted to the theory of space charge limited conduction mechanism, from where the density of localized states has been calculated. Temperature dependent DC conductivity has been reported in the temperature range of 290-390 K, which shows that the conduction is due to thermally activated tunneling of charge carriers in the band tails of localized states near Fermi level. The addition of Zn in Cd-Se system results an increase in density of localized states and hence increase in electrical conductivity.