Raman spectroscopy was conducted to study the vibrational properties and the strain status of the films. The spectra are shown in Fig. , where the spectrum of a bare 4H-SiC substrate is also shown for reference (the bottom curve). Two of the Raman modes allowed in the backscattering geometry, E2(high) and A1(LO), are observed in all samples, but instead of sharp peaks we observe significantly broadened bands peaking approximately at 585 cm -1 and 489 cm -1 , close to the positions of these modes in a relaxed, single-crystalline wurtzite InN grown along the c-direction. The A1(TO) Raman mode is forbidden in the backscattering geometry, but appears in our spectra as a band positioned around 450 cm -1 . Both the broadening of the Raman modes and the appearance of the forbidden A1(TO) can be understood by the grained structure of the films. According to our TEM analysis, the grains are in nanometer-scale defined by the thickness and the "in-plane irregularities". The existence of grains aligned along the c-