Raman spectra of thick epitaxial GaN layers formed on SiC by the sublimation sandwich method

The Raman spectra of thick ($\sim$100 $\mu$m and more) GaN layers grown on crystalline SiC substrates by the sublimation sandwich method are studied. Good agreement between the spectra of the SiC substrates used in the study and published data indicates that the measurements made in the study are reliable. The minimum difference between the results of the measurements and published evidence for GaN layers means that the layers grown by the sublimation sandwich method in the study compare well with those fabricated by the metalorganic vapor phase epitaxy (MOVPE) or chloride-hydride vapor phase epitaxy (CHVPE) techniques.