Theoretical Study of Hydrogen Adsorption on the GaN(0001) Surface
NAVAL RESEARCH LAB WASHINGTON DC
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Ab initio density functional theory, using the B3LYP hybrid functional with all-electron basis sets, has been applied to the adsorption of H on the 0001 surface of wurtzite GaN. For bulk GaN, good agreement is obtained with photoemission and X-ray emission data for the valence band and for the Ga 3d and N 2s shallow core levels. A band gap of Eg 4.14 eV is computed vs the experimental value at 0 K of 3.50 eV. A simple model, consisting of a 2 2 structure with 34-monolayer ML of adsorbed H, is found to yield a density of states in poor agreement with photoemission data for H adsorbed on surfaces prepared by ion bombardment and annealing. A new model, consisting of co-adsorbed Ga 14 ML and H 12 ML, is proposed to account for these data.
- Physical Chemistry