Highly localized electron energy loss spectroscopy was carried out by using scanning transmission electron microscopy in the energy loss regime at the band-gap, and at the N near-edge structure of cross-sectional structures. An attempt was made to determine changes in the intensity distribution and the onset energy of inelastic scattering (bandgap-related energy) of hetero-interfaces, quantum wells and dislocations. First-principles calculations, performed within the local-density approximation to density-functional theory, were used to simulate low electron energy-loss spectra. Tests in which these were compared with experimental low-loss spectra revealed good agreement of the position and shape of the spectral features. A study was made of the scattering intensity around the onset and the position of the onset energy in locations along the projection lines of isolated dislocations.

Band-Gap Related Energies of Threading Dislocations and Quantum Wells in Group-III Nitride Films as Derived from Electron Energy Loss Spectroscopy. A.Gutiérrez-Sosa, U.Bangert, A.J.Harvey, C.J.Fall, R.Jones, P.R.Briddon, M.I.Heggie: Physical Review B, 2002, 66[3], 035302 (10pp)