Electronic structure of GaN andInxGa1−xNmeasured with electron energy-loss spectroscopy

Abstract

Electron energy-loss spectroscopy has been used to study the electronic structure of GaN and ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{N}.$ The fine structure on the ionization edges was seen to change with In concentration and these changes agreed well with the results of calculations using the full-potential linearized augmented plane-wave method. Best agreement was observed when the effects of the core hole were included. The anisotropy in the electronic structure of GaN was observed in both the experimental and calculated ionization edges. The low-loss region of the spectrum also varied with In concentration, with the most obvious change being a large shift in the plasmon energy. Interband transitions were found to have a large effect on the plasmon energy in this system. Band gaps and other optical properties were determined from the low-loss spectra.