The Effect of Lattice Relaxation on Nitrogen Incorporation in GaAsN(Bi) Alloys

Due to the significant band gap narrowing and complementary strain induced by dilute fractions of N and Bi in GaAs, dilute nitride-bismide alloys are of significant interest for near to mid-infrared applications. However, N-related point defects often lead to degraded minority carrier transport and reduced optical efficiencies. For dilute GaAsN alloys, ~20% of N shares an As site with either As or another N, termed (N-As)_As or (N-N)_As split interstitials.¹ Using channeling-nuclear reaction analysis in combination with Monte-Carlo-Molecular Dynamics (MC-MD) simulations along the [100], [110], and [111] directions, (N-As)_As was identified as the primary interstitial complex.² However, the effect of lattice relaxation in the vicinity of incorporated N was not considered. Here, we use density functional theory to compute the relaxed structures of GaAs containing N_sub, (N-As)_As, and (N-N)_As, which are subsequently input into MC-MD simulations along the [100], [110], and [111] directions. We compare the computed yield trends with those measured for GaAsN and GaAsNBi alloys.