Oscillator strengths for the intersubband transitions in GaAs/InGa1–xAs quantum wells and its strain dependence

The band structure, interband and oscillator strengths for valence intersubband transitions have been theoretically calculated for highly strained InxGa1–xAs/GaAs quantum wells with different indium concentrations xIn within the k.p method where matrix Hamiltonian is solved by iteration with the Bir – Pikus strain Hamiltonian. It is shown that the oscillator strengths for valence intersubband transitions between all confined hole states decreases monotonically at increasing xIn values in the case of large strain. We did found that the transition rate is reduced by the strain effect and the calculated intersubband transition energies are shifted by approximately 40 – 80 meV. Moreover, we can predict that the optical performance of the low-dimensional systems is more convenient for lower indium concentration in the mid-infrared than that of the higher one. Finally, the results of this work are consistent with the available experimental and theoretical data.