  Electronic structures of Zn$_{1-x}$Co$_x$O have been investigated using
photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The
Co 3d states are found to lie near the top of the O $2p$ valence band, with a
peak around $\sim 3$ eV binding energy. The Co $2p$ XAS spectrum provides
evidence that the Co ions in Zn$_{1-x}$Co$_{x}$O are in the divalent Co$^{2+}$
($d^7$) states under the tetrahedral symmetry. Our finding indicates that the
properly substituted Co ions for Zn sites will not produce the diluted
ferromagnetic semiconductor property.
