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 ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}}_{1-x}{\mathrm{Al}}_x\mathrm{As}$ and ${\mathrm{Zn}}_{1-x}{\mathrm{Cd}}_x\mathrm{S}\mathrm{e}/\mathrm{Z}\mathrm{n}\mathrm{S}\mathrm{e}$ 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.