Tight-binding branch-point energies and band offsets for cubic InN, GaN, AlN and AlGaN alloys

Abstract

Starting with empirical tight-binding band structures, the branch-point (BP) energies and resulting valence band offsets (VBOs) for the zincblende phase of InN, GaN and AlN are calculated from their k-averaged midgap energy. Furthermore, the directional dependence of the BPs of GaN and AlN is discussed using the Green's function method of Tersoff. We then show how to obtain the BPs for binary semiconductor alloys within a band-diagonal representation of the coherent potential approximation (CPA) and apply this method to cubic AlGaN alloys. The resulting band offsets show good agreement to available experimental and theoretical data from the literature. Our results can be used to determine the band alignment in isovalent heterostructures involving pure cubic III-nitrides or AlGaN alloys for arbitrary concentrations.

10 pages, 6 figures

References in corpus (4)

• Consistent set of band parameters for the group-III nitrides AlN, GaN, and InN
• Excitonic properties of strained wurtzite and zinc-blende GaN/Al(x)Ga(1-x)N quantum dots
• Determination of the valence band offset at cubic CdSe/ZnTe type II heterojunctions: A combined experimental and theoretical approach
• Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys