In the last decade, we have seen a very rapid and significant development in Raman scattering characterization of GaN and related nitrides: The Γ-point phonon frequencies are lined up for a binary compound family, GaN, AlN, and InN, of both cubic and hexagonal phases. Variation of phonon spectra with atomic composition has also been intensively studied on ternary compounds. Precise evaluation of strain, compositional fluctuation, defects, impurities and so on has now become possible based on these results. Besides lattice properties, analysis of coupled modes between LO phonon and plasmon has enabled characterization of electronic properties such as carrier density and mobility. This article briefly reviews present status of Raman scattering studies on GaN and related compounds and discuss future directions.
