Raman spectra of CuIn1-x GaxSe2 (0 < x less than or equal to 0.29) thin films were measured at room temperature and low (similar to 10 K) temperature to examine the Raman active modes in the films for different x values. The variation of the most intense mode (A(1) mode) with frequency was studied and was compared with the theoretical plot. Although anion is not being substituted in the films (for different x), its mass was found to influence the Raman shift in the system. Optical band gaps of Cu(In,Ga)Se-2 films were found to vary with x showing a bowing effect. (C) 2002 Elsevier Science B.V. All rights reserved.