Influence of surface oxidation on the valence electron energy-loss spectrum of wurtzite aluminum nitride

摘要

The influence of surface oxidation on the low-loss spectrum of aluminum nitride (A1N) is investigated in electron energy-loss spectroscopy with scanning transmission electron microscopy. Contrary to intrinsic bulk A1N, oxidized A1N exhibits considerable spectral broadening both in the full width at half maximum of bulk plasmon and the subsidiary features. The modification in the low-loss lineshapes due to oxidation significantly complicates the determination of the dielectric function intrinsic to A1N. Simulations based on dielectric theory qualitatively consist with the experimental results while incorporating thick overlayers, further suggesting that the surface oxide of A1N can be rough and porous in nature.