Evolution of valence-band alignment with nitrogen content in GaNAs∕GaAs single quantum wells

We report on experimental evidence for the transition of valence-band alignment from type I to type II in GaNxAs1−x∕GaAs single quantum wells by photoreflectance measurements. The substitutional nitrogen content covers a range of 1.4%–5.9%. The turning point of the type I–type II transition occurs at x≳4.7%. The experimental observations can be well interpreted by a combination of band anticrossing model and model-solid theory when nonlinear behavior of either the shear deformation potential or the average valence-band energy is taken into account. The effect of dilute nitrogen on the valence-band offset of GaNAs∕GaAs quantum well structure is hence clarified.