Effect of gamma irradiation on optical parameters of AgSbSe2 films

Bulk AgSbSe2 was prepared by melting the constituent element in stoichiometric proportion.;The ternary composition thus obtained was found to posses an NaCl type structure. AgSbSe2 films were prepared by thermal evaporation under vacuum (10(-5) Torr) on clean glass substrates. The optical constants [absorption coefficient (alpha), absorption index (k), and the refractive index (n)], of un-irradiated and different gamma doses irradiated AgSbSe2 films, in the range from 500 to 900 nm, were obtained. The value of optical energy gap of AgSbSe2 films was found to be 1.79 eV. and it increases to 1.82 eV. with increasing the radiation doses from 1.5 Mrad to 2.0 Mrad then, decreases to 1.8 eV. for 2.5 Mrad. The influence of irradiation on the optical gap was explained in terms of diminiution of disorder and defects in the structural bonding.