HIGH FIELD CONDUCTION IN AMORPHOUS Se70Te30-xZnx THIN FILMS

The present paper reports the d. c. conductivity measurements at high electric fields in vacuum evaporated thin films of amorphous Se70Te30-xZnx. 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, non ohmic behavior is observed. The experimental data fits well with the theory of space charge limited conduction (SCLC) in the high electric field region. From the fitting of the data, the density of defect states near Fermi level is calculated. Composition dependence of DOS is discussed in the paper.