Band-gap energy of InxGa1-xNyAs1-y as a function of N content -: art. no. 085313

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 Gamma 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.