Influence of radiation on the optical parameters of AgInSe₂ films

Abstract

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 γ-irradiated films at 0.5, 1.25, 2.75 and 3.5 Mrad were calculated. For the high γ 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 (∊₁, ∊₂) were also calculated for irradiated films.

Key Words:

• Optical properties
• Thin films
• Irradiation
• Ternary compounds