Influence of γ-irradiation on the optical and electrical properties of Se(0.85) Te(0.15) films

Se-(0.85) Te-(0.15) films were prepared by thermal evaporation under vacuum on glass substrate. The optical and electrical properties of as deposited and irradiated Se-(0.85) Te-(0.15) films with different gamma-doses are reported. The optical constants (absorption coefficient (alpha), extinction coefficient (k), refractive index (n) and dielectric constants (<(epsilon)over bar>, (epsilon)double over bar)} of unirradiated and irradiated films were calculated. The value of allowed direct optical energy gap of Se-(0.85) Te-(0.15) films increased from 1.47 eV. to 1.72 eV. with increasing the gamma-doses to 2.5 Mrad. The irradiated films have lower resistivity than those as deposited films (unirradiated). The activation energy (Delta E) increases from 0.72 eV. to 0.86 eV. with increasing gamma-doses to 2.5 Mrad.