THE INFLUENCE OF MANGANESE DOPING ON THE OPTICAL-PROPERTIES OF ZINC-SULFIDE FILMS

Manganese doped (0 to 10%) zinc sulphide films have been prepared by vacuum evaporation. The films are polycrystalline and the lattice constants do not change with Mn mol.%. The optical transmission has been recorded in the wavelength range 300-900 nm. The optical band gap and refractive index have been evaluated. The band gap of these films varies from 3.48 eV (undoped) to 3.70 eV (10% Mn). The refractive index dispersion data have been fitted to the single oscillator model. The average oscillator strength S(o) (1 x 10(14) m-2) is constant with Mn doping and the refractive index dispersion parameter E(o)/S(o) varies from 6.75 x 10(-14) eV m2 (undoped) to 6.24 x 10(-14) eV m2 (10% Mn). The variations in band gap and refractive index dispersion parameter have been discussed.