Influence of Rapid Thermal Annealing on Raman Scattering of InN Epilayers

We studied the Raman scattering of the InN epilayers with rapid thermal annealing (RTA). The longitudianl optical (LO) phonon in Raman spectrum shifts toward lower frequency and increases asymmetric broadening as the RTA temperature is increased. We suggest that the formation of indium-related defects, such as metallic indium clusters or indium vacancies, are responsible for the change in the asymmetric ratio in the LO mode. The E 2 (high) mode in the Raman spectrum does not exhibit significant change after RTA since the indium atom does not involve the E 2 (high) mode.