Inelastic electron scattering in amorphous silicon nitride and aluminum oxide with multiple-scattering corrections

Electron-energy-loss measurements for an amorphous chemical-vapor-deposited silicon nitride film and evaporated sapphire in the broad energy range 1--200 eV are investigated. A method, not requiring the zero-loss peak, to remove the multiple scattering is discussed, applied, and the optical constants obtained. An Elliot-type model used with aluminum oxide gives a valence-exciton binding energy of 1.36±{}0.2 eV with a band gap of 9.8±{}0.2 eV. The unexpected strength of the nitrogen 2s transition is noted in silicon nitride.