Stokes shift in one-side modulation-n-doped-strained GaxIn1 − xAs/InP asymmetric quantum well

The effects of strain on the Stokes shift in one-side modulation-dopedGa_xIn_1 − xAs /InP asymmetric quantum wells (AQWs) are systematically investigated. By making use of a self-consistent Poisson–Schrödinger solver in the frame of a finite difference method, the quasi-Fermi levels and the band bending are determined under the effective mass approximation. The central-zone valence-band structures for compressively strained and tensile strained AQWs were calculated by making use of a four-band Luttinger–Kohn Hamiltonian. It was found that the strain influences the relative positions of the heavy-hole HH₁and the light-hole LH₁subbands and that the Stokes shifts are greatly reduced by tensile strain in the case of a Ga_0.6In_0.4As /InP AQW. Moreover, it was found that due to the presence of the two-dimensional electron gas the Stokes shifts in AQWs are much larger than the corresponding ones for a square quantum well. Also, the variation of the Stokes shift with spacer layer width for compressively strained AQWs was found to be more rapid than that for tensile strained AQWs.