GaN epitaxial layers grown on 6H-SiC by the sublimation sandwich technique

Abstract
We report on the structural and optical properties of GaN epitaxial layers grown on 6H‐SiC. We employed the sublimation sandwich method to grow single crystal layers at high growth rates with free carrier concentrations of 2×1017 cm−3. Very narrow x‐ray diffraction peaks of the GaN (0002) plane are obtained indicating the high quality of this system. These findings are directly reflected in the optical properties. The photoluminescence shows a single sharp exciton line with a half width of 4 meV. Impurity related donor acceptor transitions are seen with very weak intensities. However, at lower energies the internal luminescence transitions of the 3d transition metal ions Fe and V are observed.