GAN EPITAXIAL LAYERS GROWN ON 6H-SIC BY THE SUBLIMATION SANDWICH TECHNIQUE

We report on the structural and optical properties of GaN epitaxial la yers grown on 6H-SiC. We employed the sublimation sandwich method to g row single crystal layers at high growth rates with free carrier conce ntrations of 2 x 10(17) cm-3. Very narrow x-ray diffraction peaks of t he GaN (0002) plane are obtained indicating the high quality of this s ystem. 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 w ith very weak intensities. However, at lower energies the internal lum inescence transitions of the 3d transition metal ions Fe and V are obs erved.