ABSTRACT
The Bethe theory for inelastic scattering has been developed to understand the detailed shape of bandgap EELS spectra. The theory shows how the matrix elements for direct and indirect transitions can be decoupled from one another and have energy dependencies of (E - Eg)1/2 and (E - Eg)3/2 respectively. The zero loss peak
was removed via a deconvolution routine which allowed this theory to be tested on a number of crystalline samples with bandgaps as low as 0.9 eV at an energy resolution of 0.22 eV. The agreement between theory and experiment is surprisingly good.
