Influence of radiation on the optical parameters of AgInSe2 films

The analysis of optical constants of AgInSe2 thin films has been discussed. That ternary chalcopyrite compound shows an allowed direct transition near the fundamental absorption edge E-g1 in addition to a transition originating from crystal-field split levels E-g2. The optical band gaps of as-deposited films and gamma -irradiated films at 0.5, 1.25, 2.75 and 3.5 Mrad were calculated. For the high gamma doses (2.75 and 3.5 Mrad) the chalcopyrite film shows a three-fold optical structure near the fundamental edge due to crystal field and spin orbit splitting of the uppermost valence band. The extinction coefficient (k), refractive index (n) and dielectric constants (epsilon (1),epsilon (2)) were also calculated for irradiated films.