Another proof of dopant incorporation is XPS after Ar + etching that reveals formation of X +3 centers. When substituting Zn in ZnO this impurities induce formation of V Zn due to a large mismatch of ionic radii. The spectral methods including photoluminescence, EPR and Raman spectroscopy all prove that V Zn and their complexes are formed as a result of doping. Moreover, EPR of As-doped ZnO contains a complex signal that corresponds not only to V Zn but also to several V Zn -complexes, one of which was determined as (V Zn -) 2 . A similar signal with g-factor between 2.001 and 2.012 was observed for ZSb01_3; however, its intensity was too low to reliably ascribe its components. Overall, it is highly likely that there are more V Zn -based defect complexes that may or may not be associated with X +3 centers. This suggestion is also supported by the Raman study. The amount of V Zn per one dopant atom estimated from Raman shift is significantly higher than 2 as one would expect for the simple As(Sb) Zn -2V Zn acceptor complex. It implies a more