Effect of nitrogen on the band structure and material gain of InyGa1-yAs1-xNx-GaAs quantum wells

The conduction subband. structure of InGaAsN-GaAs quantum wells (QWs) is calculated using the band anticrossing model, and its. influence on the design of long-wavelength InGaAsN-GaAs QW lasers is analyzed. A good agreement with experimental values is found for the QW zone center transition energies. In particular, A different dependence of the effective bandgap with temperature when compared to the equivalent N-free structure is predicted by the model and experimentally observed. A detailed analysis of the conduction subband structure shows that nitrogen strongly decreases the electron energies and increases the effective masses. A very small N incorporation is also found to increase the nonparabolicity, but this effect saturates for higher nitrogen contents. Both the In content and well width decrease the effective masses and I nonparabolicity of the conduction subbands. Material gain as a function of the injection level is calculated for InGaAsN-GaAs QWs for moderate carrier densities. The peak gain at a fixed carrier density is found to be reduced, compared to InGaAs, for a small N content, but this reduction tends to saturate when the N content is further increased. For the gain peak energy, a monotonous strong shift to lower energies is obtained for increasing N content, supporting the feasibility of 1.55-mum emission from InGaAsN-GaAs QW laser diodes.