Electronic structure of ${\mathrm{In}}_y{\mathrm{Ga}}_{1-y}{\mathrm{As}}_{1-x}{\mathrm{N}}_x/\mathrm{GaAs}$ multiple quantum wells in the dilute-N regime from pressure and $\mathbf{k}\cdot \mathbf{p}$ studies

We report photomodulated reflectance measurements of several intersubband transitions for a series of as-grown ${\mathrm{In}}_y{\mathrm{Ga}}_{1-y}{\mathrm{As}}_{1-x}{\mathrm{N}}_x/\mathrm{GaAs}$ multiple quantum well samples as functions of hydrostatic pressure (at room temperature) and temperature (at ambient pressure). The experimental results provide support for the effects of disorder due to different nearest-neighbor N-cation configurations. The quantum well transition energies obtained from the photomodulated reflectance spectra are fitted as a function of pressure with a realistic 10 band $\mathbf{k}\cdot \mathbf{p}$ Hamiltonian, that includes tight-binding-based energies and coupling parameters for the N levels. The quality of match between theory and experiment confirms the theoretical model and predicts some important material parameters for dilute-N InGaAsN alloys.