Luminescence in Organic Silicons Prepared from Organic Precursors in Plasma Discharges

Summary.  The photoluminescence of plasma-prepared polysilanes during the change from linear 1D Si chains to an amorphous 3D Si network was studied. The excitonic absorption band with a maximum at 353 nm in 1D Si experiences a blue shift and broadening upon introduction of branching and networking defects. With the gradual transition from 1D to 3D structure, an extensive redistribution of oscillator intensity along the absorption edge, accompanied by a decrease of the resolution of the σ-σ^* band, was observed. In the short wavelength region of the excitation spectra there is an enormous increase of excitonic emission at 328 nm. This effect is tentatively attributed to the excitation of the phenyl group or to the phenyl-silicon bond as confirmed by effusion spectra of the phenyl species. Received July 10, 2000. Accepted (revised) September 8, 2000