New optical oxygen-deficient centers in 80 keV Re-implanted amorphous silica

The formation of radiation-induced defects in amorphous SiO2 under the implantation with Re ions was studied by optical absorption and photoluminescence spectroscopies. A new type of oxygen-deficient center, denoted as ODC/Re, has been discovered. The origin of ODC/Re is associated with disturbing influence of Re ions located in the nearest environment of ODCs and causing a change in their energy structure. The absorption and emission bands of Re-modified ODC occur with participation of singlet S-1 and triplet T-1 excited states, adiabatic terms for which are shifted relative to those for typical Si-ODC. Spectral characteristics of absorption and photoluminescence of ODC/Re along with emission kinetic parameters allow us supposing that the structure of center is close to the ODC(II)-type. Thermal annealing leads to an increase in the emission intensities by a factor of three for both Si-ODC and ODC/Re.