Intersubband absorption in strained AlxGa1−xN/GaN quantum wells with InyGa1−yN nanogroove layers

The intersubband absorption in a four-energy-level system consisting of a strained AlxGa1−xN/GaN quantum well with an InyGa1−yN nanogroove layer is calculated by considering the strain modification on the material parameters and polarization effect. It is found that the InyGa1−yN nanogroove layer in the middle of quantum well can enhance the confinement of electrons and their energy levels which consequently affect the intersubband absorption. With increasing the In composition and the groove thickness or applying a moderate compressive stress, an inflexion of energy levels appears when the lowest energy potentials of the left well and the groove are equivalent. The intersubband absorption spectrum exhibits multiple peaks contributed by different transitions. The position and height of absorption peaks are sensitive to the structural parameters (i.e., In composition and nanogroove thickness) and the strain induced by the groove layer.

► We study intersubband absorption in strained step quantum wells.
► The nanogroove layer enhances quantum confinement on electrons.
► An inflexion of energy levels appears.
► The shape of absorption lines is sensitive to strain and nanogroove layer.