We prepared an ordered oxide adlayer with (root3 x root3)R30 degrees periodicity on carbon-terminated 6H-SiC(0001) by means of a hydrogen microwave plasma. This adlayer was investigated by X-ray induced photoelectron spectroscopy (XPS) and angle resolved ultra-violet photoelectron spectroscopy (ARUPS). The XPS results are in good agreement with the recently published atomic structure of the adlayer. The ARUP spectra reveal oxygen derived surface states at 6, similar to 10, and 24 eV binding energy and a dangling bond state 0.4 eV above the valence band maximum. The band bending of 1.1 eV is compatible with a description of the dangling bond state as the lower Hubbard band with a Hubbard U of > 1.4 eV.