Photoemission study of Zn_1−<i>x</i>Co_<i>x</i>O as a possible DMS

Abstract

Abstract We report a photoemission spectroscopy (PES) and X‐ray absorption spectroscopy (XAS) study for bulk Zn 1− x Co x O samples ( x = 0 and 0.1). Both the Co 2p XAS and the Co 2p core‐level PES spectra show that the doped Co ions in Zn 1− x Co x O are in the divalent Co 2+ (d 7 ) states under the tetrahedral symmetry. A Co 2p → 3d resonant photoemission spectroscopy measurement shows that the Co 3d states lie near the top of the O 2p valence band. This work suggests that the doped Co ions in Zn 1−x Co x O substitute properly for the Zn sites with Co 2+ valence states. (© 2004 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)