Electron structure modification of interfaces in SiO2 glass with PbO nanoparticles at gamma-irradiation.

Widely used SiO2-PbO glasses can be a good model for studying electron structure of insulator-metal interface with many Si-O-Pb bonds and eutectic Pb-Si mixture. Gamma-radiation of 60Co with an energy of -1.25 MeV generates efficiently electronic and hole structure defects at these interfaces, which are detected with the resonance optical absorption technique. We studied absorption spectra of polished plates of SiO2 glass with 24% PbO after the irradiation to doses 10(4)-10(6) R at 467 R/s and 300 K. Prior the irradiation there are narrow resonances at 220 nm (oxygen deficient SiO3 centers) and also 285 and 310 nm (transversal and longitudinal plasmons on the rod like Pb-nanoparticles). After irradiation in the above mentioned dose interval the longitudinal plasmon wavelength increases up to 500 nm and that of transversal one decreases down to 260 nm that evidences almost 2-times elongation of the nanoparticles. Respectively, there occurs 10-times growth of the charge carrier density that can ensure a higher value of electric conductivity at the metal-insulator interfaces.