Novel Er-doped SiC/SiO2 nanocomposites: Synthesis via polymer pyrolysis and their optical characterization

Erbium activated SiC/SiO2 nanocomposites doped with Er3+ concentrations ranging from 1 to 4 mol% were prepared by pyrolysis of sol-gel derived precursors. The gels were obtained from modified silicon alkoxides containing Si-CH3 and Si-H groups. Thin discs obtained from the monolithic xerogels were pyrolyzed in an alumina tubular furnace in flowing Ar (100 ml/min) at 800, 1000, 1200 and 1300 °C. The samples were investigated by absorption and photoluminescence spectroscopies. Emission in the C-telecommunication band was observed at room temperature for all the samples upon continuous-wave excitation at 980 or 514.5 nm. The shape of the emission band corresponding to the 4I13/2 → 4I15/2 transition is found to be independent both on Erbium content and excitation wavelength, with a Full Width Half Maximum (FWHM) of 48 nm. By increasing the pyrolysis temperature the intensity of the luminescence increases and the electronic bandgap energy decreases.