Characterization of GaN/InGaN hetero-structures by Raman spectroscopy, PL and CL

InGaN samples grown by MOVPE were investigated by micro-Raman spectroscopy, photoluminescence and spectrally-resolved cathodo-luminescence. These methods allowed the precise determination of the Indium distribution at the micro and macro scale. The In molar fraction in the films tends to increase from centre to edge of the 2" wafers. We also noted that for increasing In content, some additional modes are seen in the Raman spectra. They are tentatively associated with the In clustering phenomena, further justified by CL spectral maps.