Radiation-induced E′ centers in SiO2 were studied in order to test the possibility of applying optically stimulated electron emission (OSEE) to the spectroscopy of excited states of point defects in dielectrics. The spectral responses of the OSEE of crystalline α quartz and silica glass irradiated by 10MeV electrons were measured and studied. It was established that volume E′ centers in the crystalline and glassy SiO2 modifications were dominant emission-active defects. Surface E’s (1) centers were also detected in glassy SiO2. A model of the energy structure of E′ centers accounting for the absence of luminescence and taking into account the presence of two non-radiative (intracenter and ionization) relaxation channels was proposed. This model was used to explain the mechanism of photothermal decay of the E′ centers and to determine the ionization activation barriers and quantum yields of these centers. The emission, spectral, and kinetic parameters of the volume and surface E′ centers in glassy SiO2 were obtained, showing the excited states of these defects to have identical atomic configurations.

Photoelectron Spectroscopy of E’ Centers in Crystalline and Glassy Silicon Dioxide. A.F.Zatsepin, D.Y.Biryukov, V.S.Kortov: Physics of the Solid State, 2006, 48[2], 245-54