Correlations between Structural, Electrical and Optical Properties of GaN Layers Grown by Molecular Beam Epitaxy

Screw and edge dislocation densities were estimated from X-ray diffraction profiles of GaN layers grown by molecular beam epitaxy. The results were confirmed by transmission electron microscopy. The layers had varying thicknesses or were deposited on differently nitridated sapphire substrates. It was found that the low temperature Hall mobility correlates with the screw dislocation density whereas the full width at half maximum of the donor bound exciton emission line changes similarly as the edge dislocation density.