Optical properties of excitons in semiconductor quantum wires.

Spectra of luminescence and linear and nonlinear absorption of semiconductor quantum wires crystallized in a transparent dielectric matrix have been investigated and interpreted in terms of excitonic transitions and filling of the exciton phase space. The calculated energies of excitonic transitions are in qualitative agreement with experimental data. The estimated values of exciton binding energies (>100 meV) in semiconductor quantum wires embedded in dielectric are a factor of several tens higher than in bulk semiconductors. The cause of this increase in the exciton's binding energy is not only dimensional quantization, but also the enhancement of Coulomb interaction, i.e. stronger attraction between electrons and holes owing to the large difference between dielectric constants of semiconductor filament and dielectric matrix.