Excitonic spectrum of an undoped quantum well in electric field

The effect of the valence band coupling on the excitonic spectrum of an undoped GaAsAl_xGa_1−xAs quantum well subjected to a normal electric field is examined. The exciton states are split because of the spin-splitting of the hole subbands. The binding energies of the (00h) and (001) excitons are noticeably increased. The transition strength of the “forbidden” (01h) exciton is enhanced both by the electric field and the strong mixing of the hole states. The binding of the 001 exciton is further increased because it exhibits a Fano-like resonance with the electron-heavy hole continuum.