We present a study on the vacuum-ultraviolet VUV absorption properties of amorphous SiO2 a-SiO2 withhigh concentrations of silanol groups Si-OH . We found that the absorption spectra are made up of a coupleof exponential profiles. The first, in the range from 7.5 to 8.1 eV, was attributed to Si-OH group absorption,while the second, in the range from 8.1 to 8.25 eV, was ascribed to the intrinsic absorption. The VUVabsorption cross section of Si-OH groups in a-SiO2 was determined as well. The intrinsic absorption was foundto be affected by the Si-OH concentration: high silanol group contents allow lower values of the Urbachenergy. This result is interpreted in terms of a reduction in the degree of disorder in wet materials.
|Numero di pagine||6|
|Rivista||PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS|
|Stato di pubblicazione||Published - 2008|
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