Multiphononon resonant Raman scattering in He~+-implanted InGaN

摘要

We present Raman-scattering measurements on InGaN epilayers with In content ranging from 17% to 42% which have been implanted with different He~+ doses. Raman spectra obtained using near-resonance visible excitation (514.5 nm) and above band-gap UV excitation (325 nm) are measured in order to study the resonant behaviour of the samples and to assess its crystalline quality. The spectra obtained with UV excitation show resonant LO multiphonon scattering up to fifth order, whose relative intensities depend on the indium concentration and implantation dose. An assessment of the degree of lattice disorder introduced by the implantation can be obtained from the analysis of the Raman spectra in terms of relative intensities and line broadenings of the multiphonon peaks.