Depth profiling of GaN by High Resolution X-ray diffraction

We present an investigation of the edge and screw threading dislocation densities in GaN- heteroepitaxial layers with different thicknesses grown on sapphire substrate using X-ray diffraction. Taking into account the finite penetration depth nature of the X-rays, we obtained depth profiles of threading dislocations along the layer thickness and attributed the observed features with annihilation centers.