Band-gap energy of ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}{\mathrm{N}}_y{\mathrm{As}}_{1-y}$ as a function of N content

The band-gap energy of InGaNAs decreases with N content at a smaller rate than that of GaNAs. Precise absorption measurements in strained InGaNAs/GaAs quantum wells on GaAs(001) are reported, and the result is explained in the frame of the repulsion between the nitrogen level and the Γ conduction band. As the energy separation between both levels is larger when the In content increases, the effect of introducing nitrogen is significantly reduced. In order to get a quantitative description of experimental results, the model includes a detailed description of the local N environment. Results suggest that in our InGaNAs/GaAs quantum wells grown by molecular beam epitaxy, the N configuration should be close to the statistical one. Using this model to explain the effect of annealing on band structure, we conclude that, on average, N atoms gain one additional nearest-neighbor In atom during the annealing, leading to a moderately large band-gap blueshift of 20–30 meV.