Dependence of the E-2 and A(1)(LO) modes on InN fraction in InGaN epilayers

The behavior of the E-2 and A(1)(LO) optical phonons in InxGa1-xN has been analyzed by Raman scattering over the whole composition range. The frequencies of the E-2 and A(1)(LO) modes decrease with increasing InN fraction. These modes display a significant broadening for an InN fraction of approximate to 60% and their linewidth decreases towards both ends of the composition range as a consequence of reduced cation disorder. Our results show a one-mode behavior for, both E-2 and A(1)(LO) modes of InGaN