Physical Review B 51, 4343 - 4346 (1995)

Quasiparticle Excitations in GaAs_1-xN_x and AlAs_1-xN_x Ordered Alloys

A. Rubio, M.L. Cohen

We have performed a quasiparticle study of the fundamental excitations in ordered alloys of III-V semiconductors, GaAs_1-xN_x and AlAs_1-xN_x. The experimentally observed anomalous redshift in GaAs_1-xN_x of the direct band edge is explained here by effects arising from the 20% lattice mismatch. The fact that the bottom of the conduction band is mainly dominated by nitrogen leads to a large reduction of the fundamental gap at Γ as the volume increases. This reduction continues until the charge density begins to locate on the arsenic site. Based on this simple scenario, we predict that a similar redshift may be observed in the indirect gap AlAs_1-xN_x alloys. Also an indirect to direct band-gap transition will be observed for intermediate N concentrations. The possibility of closing the band gap is discussed in terms of the quasiparticle results.

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http://dx.doi.org/10.1103/PhysRevB.51.4343

Related Research Areas

• Nanostructures and nanotubes. Nanocapilarity