Energy levels and intersubband transitions inInGaAsN∕AlGaAsquantum wells

Abstract

We calculate the energy of quantified levels in $\mathrm{In}\mathrm{Ga}\mathrm{As}\mathrm{N}∕\mathrm{Al}\mathrm{Ga}\mathrm{As}$ quantum wells by using an analytical model based on the band anticrossing model and the repulsion by the nitrogen level. We show that the presence of nitrogen in InGaAsN quantum wells introduces peculiarities in the band structure. In quantum wells with a low confinement, energy levels are simply pushed towards the bottom of the well. When the confinement becomes large enough to support subbands above the localized nitrogen level, subbands are split and have a dispersion strongly affected by the repulsion by the $N$ level. In this case, intersubband transitions are deeply modified, with a splitting of the transitions and important spectral shifts of the lines. Due to the admixing of nitrogen wave function in the electron wave function, the amplitude of the intersubband transitions decreases. The predicted effects are a clear test for the band anticrossing model on the one hand, and may have a strong impact on applications in the infrared on the other hand.