Polaronic excitons in a GaAs/Ga1−xAlxAs double-quantum-well semiconductor heterostructure

Binding energies of a hydrogenic donor impurity in a GaAs/Ga1−xAlxAs double quantum well are investigated. We have applied the variational method using a ground state hydrogenic wavefunction, in the framework of the single-band effective mass approximation. The binding energy is calculated for different Al contents and different barrier sizes. A position dependent binding energy is reported for different well widths. The donor exciton binding energy with the inclusion of valence band anisotropy is investigated as a function of the well width. The 2D Hartree–Fock spatial dielectric function and polaronic effects have been employed in our calculations. The results show that the binding energy is higher when the impurity is at the well centre and lower when the impurity is at the barrier centre. The exciton binding energy is enhanced upon the inclusion of the spatial dielectric function and the polaronic effect. The exciton has an influence on the interband emission energy. The results are compared with ones from the available literature.