Confinement effects and polarization dependence of luminescence from monolayer-thick Ge quantum wells

We have investigated the luminescence from monolayer-thick Ge quantum wells pseudomorphic to Si(100) substrates. The electronic structure of these quantum wells was investigated by uniaxial stress, and polarization- and temperature-dependent electroluminescence. By identifying the symmetry and origin of the wave functions involved in the optical transitions, it was found that both the confinement in the thin wells, as well as the interface between the wells and the surrounding material, play an important role for the emission.