Micro-Raman scattering study of hexagonal InGaN epitaxial layer

Hexagonal InxGa1-xN film grown by metalorganic chemical vapor deposition (MOCVD) was studied by Micro-Raman scattering and X-ray diffraction. The phase separation was observed in InxGa1-xN, the biaxial stress was measured by both Raman and X-ray diffraction. In Raman spectroscopy, the A1(LO) mode of InxGa1-xN is absent. Instead, the LO phonon-plasmon coupled mode (LPP+) was observed at about 778 cm-1. The carrier concentration was determined by the frequency of the coupled mode. The E2 and A1(TO)modes of InxGa1-xN layer exhibit a down-shift compare to those of GaN layer. At low temperature, the peak induced by electronic transition was observed in Raman spectra of InxGa1-xN.