Al L core edge fine structure in Al, AlN and α-Al₂O₃: A comparison of microelectron energy loss spectra with theory

The Al L near-edge fine structures of aluminum and its compounds with nitrogen and oxygen are studied using electron energy loss microspectroscopy in a transmission electron microscope. These edges are normalized to the same scattering cross section per Al atom per electronvolt. The cross section is calculated by using the Born approximation. The contributions to the cross section are from the valence shell crystal states obtained by using the extended Hückel band calculation and the ionization states obtained by using the electron gas model. The chemical effects in the ionization region are taken into account by including the contributions from the elastic backscattering of outgoing plane waves by the atoms that neighbor the excited atoms. The results by theoretical calculation agree semiquantitatively with experimental results.