Surfactant-Induced Chemical Ordering of GaAsN:Bi

We have examined the influence of an incorporating surfactant on chemical ordering in GaAsN:Bi alloys. Epitaxy with a (2 × 1) reconstruction leads to the formation of GaAsN alloys, while the introduction of a Bi flux induces long-range chemical ordering of the {111} planes of GaAsN:Bi. We propose a mechanism in which Bi enhances the alignment of dimer rows along the [110] direction, facilitating N incorporation beneath surface dimers and Bi incorporation between dimer rows to form alternating N-rich and Bi-rich {111} planes. These findings suggest a route to tailoring the local atomic environment of N and Bi atoms in a wide range of emerging dilute nitride-bismide alloys.