Optical properties of excitons in CdS semiconductor-insulator quantum wires

The characteristic features of the luminescence spectra of CdS semiconducto r nanocrystals, crystallized in hollow channels in a dielectric template, a re explained in terms of excitonic transitions in semiconductor-insulator q uantum wires. The excitonic transition energies agree with the values calcu lated taking into account the effects of size quantization and the "dielect ric enhancement of excitons" - the large increase in the electron-hole attr action as a result of the difference between the permittivities of the semi conductor and insulator. The theoretically computed binding energies of exc itons in CdS quantum wires with a diameter of 10 nm reach 170 meV. It is sh own that the excitonic transition energy is constant for a wide range of wi re diameters. (C) 1999 American Institute of Physics. [S0021-3640(99)01115- 9].