Space charge limited conduction in a-Se75In25−xPbx thin films

The present paper reports the d.c. conductivity measurements at high electric fields in vacuum evaporated thin films of amorphous Se75In25−xPbx (0 < x < 10). Current-voltage (I-V) Characteristics have been measured at various fixed temperatures. In all the samples, at low electric fields, ohmic behavior is observed. However, at high electric fields (E∼ 104 V/cm), non-ohmic behavior is observed. In case of sample having 4 at.% of Pb, the experimental data fits well with the theory of space charge limited conduction (SCLC). From the fitting of the data, the density of defect states near Fermi level is calculated. Such type of behavior is not observed at higher concentration of Pb in the present glassy system.