Phonon lifetimes and phonon decay in InN

We report on the Raman analysis of A(1)(LO) (longitudinal optical) and E-2 phonon lifetimes in InN and their temperature dependence from 80 to 700 K. Our experimental results show that among the various possible decay channels, the A(1)(LO) phonon decays asymmetrically into a high energy and a low energy phonon, whereas the E-2 phonon predominantly decays into three phonons. Possible decay channels of the A(1)(LO) phonon may involve combinations of transverse optical and acoustic phonons. Phonon lifetimes of 1.3 and 4 ps were measured at 80 K for the A(1)(LO) and the E-2 phonons, respectively. This rather long A(1)(LO) phonon lifetime suggests that hot phonon effects will play a role in InN for carrier relaxation.