GaN thin film materials, un-doped, Si- and Mg-doped, have been grown on c-sapphire substrates by low pressure metalorganic chemical vapor deposition, and have been characterized by micro-Raman scattering ((mu) -RS) and micro- photoluminescence ((mu) -PL) spectroscopy. Basic Raman scattering modes, and in particular, their variations have been observed with the laser incident on the cross section of a few micron thick GaN film. Raman line shape analysis on the E2 mode is presented, based upon the spatial correlation theoretical model. Through the theoretical modeling of the LO-phonon-plasmon coupling, the free carrier concentration can be determined via Raman measurements and curve fitting. Using a newly designed and developed UV Raman-PL microscope system, room temperature PL and its variation with the SiH4 doping level for a series of n- type GaN epitaxial materials have been studied. Combined UV (mu) -RS-PL spectra from p-type GaN are also investigated.