Characterization of edge dislocation density through X-ray diffraction rocking curves

A detailed geometric model for calculating the edge dislocation density through X-ray diffraction rocking curves is proposed in this study. Based on this model, we deduce a new formula to evaluate the edge dislocation density from the full-width at half-maximum values of skew symmetric rocking curves. The widely used formula proposed by Srikant et al. is an approximate result of this formula. The fitting results obtained by the two formulae coincide well from the measurement data of gallium nitride films grown on silicon substrate.