In this thesis I document the growth of InN above accepted decomposition temperatures of 630°C and discuss the analysis of the Fourier-transform infrared spectroscopy measurements of InN properties. InN films were grown by MEPA-MOCVD at growth temperatures ranging from 700 to 957 °C. The evidence of InN presence in grown films is presented from infrared spectroscopy, X-ray diffraction studies, Raman spectroscopy, and atomic force microscopy. The data and previous studies indicate polycrystalline grainy InN film partially with dominant epitaxial material crystallographically locked to the substrate. The mathematical modelling of infrared reflectance and comparison with data is performed for non-polarized light. A model is applied to extract thickness, carrier concentration and phonon frequencies for InN film grown on sapphire. The developed model can be refined to analyze other III-Nitride materials, including multilayer heterostructures as the optoelectronic calculations are similar for this class of material.