Formation of Silver Nanoparticles in Photothermorefractive Glasses during Electron Irradiation

The formation of silver nanoparticles in photothermorefractive glasses during electron irradiation and subsequent heat treatment is experimentally studied. The optical density spectra of samples at various stages of heat treatment are compared. The formation of metallic nanoparticles is shown to occur during both electron irradiation and subsequent heat treatment. Nanoparticles are localized in layers parallel to the surface. At the initial stage of nanoparticle formation, the key role is played by the appearance of a negative bulk charge in the near-surface layer in glass, which results in the field-assisted migration of positive metal ions and a characteristic layered distribution of metallic nanoparticles in the glass volume.