Comment on "Optical characterization of CuIn1-xGaxSe2 alloy thin films by spectroscopic ellipsometry" [J. Appl. Phys. 94, 879 (2003)]

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, epsilon(omega)=C-Ae(i phi)(omega-E+i Gamma)(n), in this comment. (c) 2006 American Institute of Physics.