Optical and electrical properties of vacuum evaporated In doped Se amorphous thin films

The de current-voltage characteristics of thin films of the metal chalcogenide glassy semiconductor Se100-x In-x with 3 less than or equal to X less than or equal to 15 using a square four-point probe of silver paste were obtained. Results showed a nearly ohmic behaviour. The resistance obeyed an Arhenius-type dependence on the ambient temperature. The optical band gap was determined and found to be in the range 1.5-1.75 eV and arose from indirect transitions. The electrical activation energy lies in the range 0.79-1.02 eV. The electrical and optical data were consistent and realized by binding energy represented by the cohesive energy values. The generalised "8 - n" rule was used to estimate the average co-ordination number. Obtained results were treated in the frame of the chemical bond approach proposed by Bicerano and Ovshinsky (Non-Cryst. solids, 1985; 74:75). Also, it was observed that the prepared films are almost stable against gamma-dose up to 10 Mrad. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.