Effect of Composition on the Optical and Electrical Conductivity of CuIn(SexS1−x)2

Optical and electrical conductivity of chalcopyrite CuIn(SexS1−x)2 (0 ≤ x ≤ 1) amorphous thin films are investigated. A transmission has been measured in a wavelength range (200 ≤ λ ≤ 2500 nm). The calculated optical energy band gap (Eg) and Urbach tail (band tail width) Eu decrease with increasing Se content. Refractive index (n) is estimated according to the Wemple–DiDomenico single oscillator model. Oscillator energy (E°), dispersion energy (Ed), and the ratio of free carrier concentration to electron effective mass (N/m*) are calculated from optical data for all thin films. Also, the high frequency dielectric constant at an infinite wavelength (e∞), lattice high frequency dielectric constant (eL) and static refractive index (n°) are determined. Electrical conductivity (σ) is obtained at room temperature.