Description:
<jats:p>A method to determine the optical functions of thin-film CuIn1−xGaxSe2 alloys was provided in the paper “Optical characterization of CuIn1−xGaxSe2 alloy thin films by spectroscopic ellipsometry.” The optical functions were obtained and the effect of Ga content on the electronic transitions of CuIn1−xGaxSe2 was discussed. We indicate the mistake of their method in determining the critical point energies and discuss the reason for using standard analytic line shape, ϵ̃(ω)=C−Aeiϕ(ω−E+iΓ)n, in this comment.</jats:p>