Published online by Cambridge University Press: 10 February 2011
We present a comprehensive study of the direct photoluminescence from excitonic states in GaN using polarization-dependent and magnetooptical measurements in fields up to 15 T. We measure and identify fine-structure splittings in the states n=l and n=2 of the A-exciton. The splitting between the energy levels of longitudinal and transverse states in the A-exciton is 0.96 meV. Emission from the spin triplet exciton in the state n=l is observed. We also identify emissions from three sublevels of the state n=2 of the A-exciton. From the analysis of our data we obtain the effective-mass parameters of electrons and holes, g-values and the Rydberg energy of the A-exciton.