Effective mass and conduction band dispersion of GaAsN/GaAs quantum wells

Recently published results for the effective mass in GaAsN/GaAs quantum wells reach values as large as 0.5m0 for 1% N in the quantum well and then a decrease with increasing nitrogen content. The effective mass was obtained by fitting experimentally measured optical transitions energies with calculated ones using a parabolic band model. In this work we arrive at different conclusions. First, we prove experimentally that the parabolic band approximation is insufficient for the case of InGaAsN and GaAsN alloys. Then we show that by taking into account the strong nonparabolicity of the conduction band, we obtain an effective mass in GaAsN/GaAs quantum wells increasing from 0.095m0 to 0.115m0 for a nitrogen content varying from 1% to 3%.