Bandgap energy model for GaInNAsSb/GaAs alloys with high N content and strain influence

•A novel interpolation method based on BAC modelling for predicting bandgap energies of dilute nitride GaInNAsSb compounds.•The influence of lattice strain is incorporated in the model.•Excellent correlation with experimental values in a relatively broad composition range including alloys with up to 8% of N. Bandgap energy of dilute nitride GaInNAsSb/GaAs alloys with N compositions as high as 8% are estimated using a method based on band anti-crossing model used for GaNAs/GaNSb/InNAs/InNSb ternary compounds. The parametrization of the model is defined by fitting with experimental composition and bandgap energy values employing a differential evolution algorithm. The effects of lattice strain on the bandgap energy are taken into account by the model resulting in an accurate prediction of the bandgap energy with an average deviation of only 12 meV compared to the experimental data. The model provides a useful tool for accurate determination of bandgap energies of dilute nitrides, including narrow bandgap, i.e. ∼0.7 eV GaInNAsSb alloys, which are becoming increasingly relevant in the development of high-efficiency lattice-matched multijunction solar cells.