Resonant Raman scattering in InGaN alloys

A strong resonant behavior of the Raman scattering from LO-phonons in n-InGaN alloys at excitation near the interband absorption threshold was observed. An approach has been developed to describe the resonant Raman cross sectional profile in the presence of a Burstein-Moss shift of the interband optical transitions. It has been shown that a simultaneous study of absorption, photoluminescence, and Raman spectra provides reliable information about the band gap and can be efficient for the alloy characterization. Our data show that the band gap composition dependence of InGaN is characterized by the strongly nonlinear behavior with the large bowing parameter of 2.5-2.6 eV.