Angle-resolved photoemission from stoichiometric GaN(0 0 0 1)-1 × 1

We present results from an angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) investigation using synchrotron radiation of a stoichiometric Ga-polar GaN(0 0 0 1)-1 × 1 sample grown by metal-organic chemical vapour deposition (MOCVD). The electronic structure of the surface was investigated with ARUPS along the Γ¯-K¯-M¯, Γ¯-M¯, and Γ-A directions of the main symmetry lines of the surface and bulk Brillouin zones. We find one surface state close to the valence band maximum (VBM) at Γ, dispersing down and emerging into the projected band gap in the region around K¯. From a comparison with a density functional theory (DFT) calculation [F.-H. Wang, P. Krüger, J. Pollmann, Phys. Rev. B 64 (2001) 035305-1], three additional surface related features are proposed, but no strongly dispersing Ga dangling bond band is observed. We find the VBM at 3.45 eV below the Fermi energy.