First-principles calculation of band-gaps reduction in GaAsN alloys and (110) growth axis GaAs/GaN superlattice

• The electronic properties of (GaAs)/(GaN) SL and GaAsN alloys is studied with the first-principle calculation.
• A comparative study between the both (001) and (110) growth axis SL is proposed.
• The band structures of both (001) and (110) growth axes is very different.
• The gap bowing which occurs in GaAsN does not occur in the same way as that in SL.

First-principles calculations are performed to study the structural and electronic properties of GaAs and GaN zinc-blende/zinc-blende superlattices using the full potential linear muffin-tin orbitals method in its plane wave approximation which enables an accurate treatment of the interstitial regions. The choice of this method ensures the present work to be free from adjustable parameters and enabled us to perform a microscopic study. The results for GaAs/GaN superlattices with both (001) and (110) growth axis are investigated and compared. We have found that bowing, which is known to occur for ternary GaAsN dilute nitrides, is absent from GaAs/GaN “dilute nitride” of (001) growth axis superlattices for N concentrations beyond 7%, but it can be obtained in the (110) system.