Double bound polaron in quantum wells

We have proposed the Hamiltonian of the single or double polaron bound to a helium-type donor impurity in semiconductor quantum wells (QWs) in the cas e of positively charged donor center and neutral donor center. The coupling s of an electron with various phonon modes are considered; in particular, t he interaction of the impurity with the various phonon modes is included. W e have calculated the binding energy of a bound polaron in Alx1Ga1-x1As/GaA s/Al-xr Ga1-xr As symmetric and asymmetric QWs. The results are obtained as a function of barrier height (or equivalently of Al concentration x), well width, and the position of impurity in the QWs. Our numerical calculations show clearly that for a thin well the cumulative effects of the electron-p honon coupling and the impurity-phonon coupling can contribute appreciably to the donor binding energy. The enhancement of polaronic effect is also fo und in the case of ionized donor.