Investigation of the photoelectric and photoluminescent properties of crystalline quartz and vitreous silica in the fundamental absorption region. A model for electronic structure and migration of energy in SiO2

Abstract

AbstractElectronic structure and energy migration in SiO2 are studied by the experimental method. The spectral dependences of the related quantum yield of external photoemission, of photoconductivity, and of energy transfer to the luminescence centres are investigated in crystalline quartz and vitreous silica under irradiation by photons with energy from the fundamental absorption region. The direct allowed transition energy gap is found to be equal to 12 eV. The energy gap minimal value is estimated to be 9.5 eV. The fundamental absorption bands of SiO2 at 10.4 and 11.6 eV are shown to be due to excitons, capable of migrating in the „hot”︁ non‐thermalized state and transferring energy to the luminescence centres. Electron‐hole pairs transfer energy in thermalized state with lattice.