Nitrogen molecules (N2) were incorporated in interstitial voids in amorphous silica (a-SiO2) thermally annealed in N2 atmosphere. The Raman band associated with the infrared N–N stretching mode of interstitial N2 (Q band) was located at ~2325/cm and was shifted to low energy compared to that of N2 molecules in air (~2330/cm). From depth profiling of the Raman band intensity in the samples thermally annealed at 800, 900 1000C, the authors determined the diffusion coefficient and solubility of N2 in a-SiO2 were found to be given by:

D (cm2/s) = 1.3 x 10−4exp[−1.28(eV)/kT]

and

S (cm3/atm)= 7.0 x 1015exp[0.07(eV)/kT]

Diffusion of Nitrogen Molecules in Amorphous SiO2. K.Kajihara, M.Hirano, Y.Takimoto, L.Skuja, H.Hosono: Applied Physics Letters, 2007, 91[7], 071904