Exciton binding energies in polar quantum wells with finite potential barriers

A theoretical method for studying the properties of 1s and 2s excitons in polar quantum wells with finite potential barriers is presented. Exciton–optical-phonon interaction together with an image-charge effect and discontinuity of the band masses are included in the theory. Exciton binding energies and exciton–LO-phonon interaction energies of GaAs/Ga_1-xAl_xAs and Zn_1-xCd_xSe/ZnSe quantum wells are calculated numerically. Our theory gives correct results throughout the entire well-width range of the finite-barrier quantum wells. The properties of the 1s and 2s excitons are found very different in quantum wells. The theoretical results of the energy difference between 1s and 2s exciton states of heavy-hole excitons in these quantum-well structures are compared with the experimental data directly. The property of the excitons in polar quantum wells are discussed in the present paper.