Surface roughness and dispersion parameters of indium doped amorphous As 2Se 3 thin films

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Both a binary amorphous system of composition As 2Se 3 and a ternary amorphous system of composition amorphous (As 2Se 3) 0.99In 0.01 with thickness in the range 150–250 nm have been prepared by thermal evaporation technique. Indium doping and thickness effects on the features of As 2Se 3 thin films have investigated. The optical transmission spectra of these films have been measured in the range 200–1200 nm where the absorption coefficient and the optical energy gap Eg are evaluated. The refractive index and surface roughness of the prepared films are found to be highly dependent on film thickness and indium doping, using Swanepoel method. The single oscillator energy ( E o) and the energy dispersion parameter ( E d) have been calculated and discussed in terms of the Wemple and DiDomenico model. The results reveal that, they are thickness dependent—both E o and E d being higher for the undoped samples than that for the doped films.