GaAs quantum well in the non-parabolic case: the effect of hydrostatic pressure on the intersubband absorption coefficient and the refractive index

Abstract

We investigated the effect of the hydrostatic pressure on the optoelectronic properties of a quantum well (QW) based on δ-doped GaAs sandwiched by Ga1-xAlxAs. We study the case of a non-parabolic conduction band where the aluminum content is set at 30%. We perform our calculations in the context of the approximation of the envelope function formalism using the finite difference method. Results show that the transition energies decrease with the increase of the hydrostatic pressure, which causes remarkable modifications on the optical properties of the QW nanostructure. The non-parabolicity effect is more important for small QW (Lw ≤ 5nm) and less marked in narrow and large QW. In addition, we study the absorption coefficient for 8 nm/4 nm/8 nm geometry. On the one hand, the pressure increase creates a displacement of the optical absorption coefficient towards low energies and a decrease of the absorption peak value. On the other hand, the refractive index moves towards higher energies. We show that in the presence of a hydrostatic pressure and following its effect on intersubband transitions, these optical properties also depend on the dopant concentration rate and the quantum well width. Our study finds interests for the nano-fabrication of quantum wells and in particular for those used in optical and electronic applications.