Abstract

Low dimensional semiconductors are expected to exhibit enhanced optical and electronic properties that are strongly influenced by the dimensionality of the quantum confinement. This makes 1-dimensional quantum wires and 0-dimensional quantum dots attractive materials for optoelectronic devices like microcavity lasers.¹ However, because fabricating high quality nanometer-scale structures is difficult, there have been no experimental studies of the optical nonlinearities in quantum wires. We report on the excitonic nonlinearities in quantum wires made from fractional-layer superlattices (FLS). We perform experiments at low temperature (17 K) where exciton-exciton interactions dominate, and at room temperature where exciton-carrier interactions are most important. To properly describe the optical nonlinearities in quantum wires we use a many-body physics approach which explicitly includes the 1-D quantum confinement.² We observe for the first time a pronounced red-shift of the excitonic energy at room temperature demonstrating that because plasma screening of the Coulomb interaction is weakened in 1-D, the band-gap shrinkage dominates at low excitation densities.

© 1996 Optical Society of America