Inelastic Light Scattering in a Onefold-Coordinated Amorphous Semiconductor

The first measurements on low-temperature-deposited thin-film a-I are reported. In situ Raman spectra indicate that a-I is a onefold-coordinated semiconductor in contrast to other amorphous solids studied to date. The spectra surprisingly differ from those of molecular systems, indicating appreciable intermolecular coupling. Considerable structural disorder is indicated by a fivefold increase in intramolecular bandwidth relative to c-I. Delocalized bonding rather than weak directional covalent interactions is suggested for intermolecular coupling in a-I.