Pb+ implanted SiO2 probed by soft x-ray emission and absorption spectroscopy

The results of soft-x-ray O Kα emission (XES) and O 1s absorption spectroscopy (XAS) measurements of Pb-implanted glassy and crystalline silica are presented. The x-ray O Kα (2p → 1s electron transition) emission spectra of SiO2 were recorded before and after Pb-implantation with the energy of 30 keV and ion fluence 5 × 1016 ion/cm2. It was found that XES O Kα of implanted samples is sensitive to the disordering degree of the oxygen sublattice. The transformations and peculiarities of the spectra shape of implanted samples are explained by the disordering and amorphization effects in the structure of Pb-implanted SiO2. Comparing the XES O Kα of reference a-SiO2, Pb-implanted SiO2 and binary glassy PbO–SiO2 system, it was established that the ion-beam treatment of oxide matrix does not generate an oxidized Pb as PbO4-type structural units. The energy band gap of 9.2 eV well coincides with previously reported data and was evaluated qualitatively with the help of overlaying the XES O Kα and XAS O 1s to the common energy scale for Pb-implanted SiO2 and binary glassy PbO–SiO2.