Optical and X-ray diffraction studies of multilayer structures based on InGaN/GaN solid solutions

Multilayer structures based on the In _x Ga_{1 ? x} N/GaN compounds grown by gas-phase epitaxy from organometallic compounds are studied using photoluminescence spectroscopy and high-resolution X-ray diffraction. A method for analyzing the experimental rocking curves of multilayer structures in terms of the Parratt-Speriosu model is developed. This method permits one to determine the thickness, period, and average composition of In _x Ga_{1 ? x} N/GaN layers, as well as the deformation of the active region in the samples under study. The local indium content is determined using the theoretical model which describes the radiation energy as a function of the thicknesses of the InGaN layers taking into account the energy of quantum confinement, the energies of the spontaneous polarization and piezoelectric polarization, and the parameters determined from high-resolution X-ray diffraction data.