X-ray spectra and electronic band structure of nitrogen in Al x Ga1−x N solid solid solutions

Abstract

The electronic energy structure of the valence band and the x-ray absorption near edge structure (XANES) region of nitrogen in AlxGa1−xN solid solutions and binary crystals of gallium nitride GaN and aluminum nitride AlN are calculated using the local coherent potential method and the cluster version of the muffin-tin approximation within the framework of the multiple scattering theory. It is demonstrated that the calculated electron densities of states correlate with the nitrogen K x-ray emission and nitrogen K x-ray absorption spectra. The electronic energy structure of the top of the valence band and the XANES region in AlxGa1−xN solid solutions are compared with those in the binary crystals of the GaN and AlN nitrides, and an interpretation of their specific features is proposed. An analogy is drawn between the evolution of the electronic energy structure of the valence band and the XANES region in the alloys under investigation and the evolution of the electronic band structure in the AlxB1−xN and BxGa1−xN alloys. General trends in the transformation of the structure and variations in properties of these alloys are discussed.