Electron energy-loss near edge structure (ELNES) of InGaN quantum wells.

Lasers and light-emitting diodes (LEDs) that emit in the blue to green region are often based on InxGa1-xN quantum well structures. Ionization edges in the electron energy-loss spectrum contain fine structures (called the energy-loss near edge structure (ELNES)) and provide information about the electronic structure. In this paper we compare the experimental and calculated ELNES for the N-K ionization edge of InxGa1-xN quantum wells. When the effects of the core-hole are included in the calculations, agreement between experimental and calculated spectra is very good. Strain has been shown to accentuate the effects of In on the ELNES and moves the ionization edge onset down in energy, relative to the other features. These results suggest that ELNES may provide an alternative method to lattice imaging to determine the presence of strain in this system.