A reciprocal-space model was developed that described the (hkl) dependence of the broadened Bragg peak-widths produced by X-ray diffraction from a dislocated epilayer. The model was compared with experiments, and it was found that it accurately described the peak-widths of 16 different Bragg reflections in the [010] zone of GaN and AlN heterolayers. Using lattice-distortion parameters determined by fitting the model to selected reflections, threading-dislocation densities were estimated for 7 different GaN and AlGaN samples. Improved agreement with transmission electron microscopy measurements was found.

Effect of Threading Dislocations on the Bragg Peak-Widths of GaN, AlGaN, and AlN Heterolayers. S.R.Lee, A.M.West, A.A.Allerman, K.E.Waldrip, D.M.Follstaedt, P.P.Provencio, D.D.Koleske, C.R.Abernathy: Applied Physics Letters, 2005, 86[24], 241904 (3pp)