Effect of copper addition on electrical and optical properties of As10Se90 thin films according to chemical bond

The du current-voltage characteristics of thin films of the metal chalcogenide glassy semiconductor As(10%)Se(90%)Cu-x with 0 less than or equal to x less than or equal to 1 using a coplanar Bold electrode were obtained. Results showed a nearly ohmic behaviour with the resistance having an Arrhenius-type dependence on the ambient temperature. The optical band gap was in the range (1.47-1.53 eV) and arose from indirect transitions; increasing the Cu content resulted in decrease of the optical gap and electrical activation energy, which was in the range 0.4-0.6eV. 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 coordination number. Obtained results were treated in the frame of chemical bond approach proposed by Bicerano and Ovshinsky.' (C) 1998 Elsevier Science Ltd. All rights reserved.