Multiferroic BiFeO3 (BFO) films have been grown on c-sapphire substrates by pulsed laser deposition under different laser energies (E-L). The X-ray diffraction and Raman spectra indicate that the films are polycrystalline and exhibit the single rhombohedral (R) phase. The crystal distortion becomes weaker with decreasing the E-L, which is described by the ratio of c/a. It was found that different E-L values also lead to the variation of the Bi/Fe ratio. Temperature-dependent Raman spectra were carried out to study the phonon mode evolution behaviors. The three A(1) transverse optical (TO) phonon modes located at 219, 172, and 142 cm(-1) shift towards a lower energy side with the temperature due to thermal expansion, thermal disorder and the anharmonic effects of lattice. The E(TO) and three A(1)(TO) phonon frequencies slightly increase with increasing the E-L of the growth condition, which results from the Bi vacancies, the changes of the length and intensity of Bi - O bonds and the local structure distortion in the FeO6 octahedra. The dielectric functions of the BFO films in the frequency range of 50-8000 cm(-1) have been extracted by fitting infrared reflectance spectra with the Lorentz multi-oscillator dispersion model. The variation trend of the dielectric functions with different E-L can be observed and related to the packing density, surface roughness, and defect states. It was concluded that the E-L corresponding to changing the c/a ratio has an obvious influence on the lattice vibrations and intraband transitions of the BFO films. (c) 2012 Elsevier B.V. All rights reserved.