Photoinduced crystallization and space charge limited current through Au/Se92.7S7.3/Au thin films

The present paper reports a study of photoinduced crystallization in thermally evaporated Se92.7S7.3 films. The photoinduced crystallization was achieved by shining white light (from 25 mW/cm2 tungsten lamp) at room temperature for different exposure times up to 5.184 Ms. The analysis of X-ray diffraction (XRD) patterns indicated that the grain size (D), the strain (ζ) and the dislocation density (δ) are photoaging dependent. The capacitance–voltage data confirmed that the relative permittivity of the films is equal to ∼10.31. Room temperature current density voltage characteristics of Au/Se92.7S7.3/Au films showed Ohmic conduction in the lower voltage range ∼<1 V, and space charge limited conductivity (SCLC) in the relatively high-voltage range. The SCLC was controlled by an exponential distribution of traps above the valence band. The temperature dependence of the current density in accordance with the theory for the exponential trap distributions allowed the calculation of some essential parameters such as; trap concentration, characteristic temperature, and the trap density.