Thin films of hydrogenated amorphous silicon-sulfur-fluorine alloys have been prepared by RF decomposition of mixtures of silane, hydrogen suflide and silicon tetraflouride dluted in Helium. The IR absorption spectra of a-Si, S, F:H alloys slow the characteristic Si-H, Si-S and Si-F induced bands. Optical transmission measurements reveal that incorporation of fluorine and/or sulfur atoms enhances the band gap of the material. An increase in the optical (Tauc) gap of the alloy films from 1.80 eV for unalloyed a, Si:H to 2.3 eV for sulfur and fluorine rich samples was observed. The phtoluminescence (PL) properties were investigated at low temperature using an argon laser as an excitation source. A correlation between the sulfur and fluorine contents in the film and the full width at half maximum (FWHM) was established. Initial nonlinear investigations on these films reavels a third order optical nonlinearties as measured using Z-scan technique.
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