Abstract

Optical properties of excitons in conventional semiconductor quantum-well structures derive from the spatial confinement of electrons and holes by variations in the electronic potential across the barrier and the well layers. However, a barrier layer with a smaller dielectric constant can substantially increase the binding energy of excitons in the well, especially when the dielectric constant in the barrier layer is sizably smaller than that in the well layer (ε_b < ε_w). Theory suggests that the binding energy of excitons in the well can substantially exceed the value of four-exciton Rydbergs, the ideal limit of the conventional two-dimensional (2D) system.

© 1992 Optical Society of America