A series of ZnMgO oxide films single doped with arsenic was grown by plasma assisted molecular beam epitaxy method. The concentration of Mg in Zn1-xMgxO alloys was evaluated on the basis of X-Ray photoelectron spectroscopy (XPS). Changes of the band gap energy in Zn1-xMgxO were evidenced by cathodoluminescence measurements. Analysis of high resolution As 3d XPS spectra revealed three arsenic states with binding energies of similar to 41 eV, 44.2 eV and 45.6 eV assigned to: deep acceptor of As-O, acceptor As(Zn-)2V(Zn) and donor As-Zn, respectively. Small concentrations of AsO species were detected in all samples. The As contribution due to As-Zn-2V(Zn) centers was found to be intensive, and increased with the concentration of Mg. (C) 2017 Elsevier B.V. All rights reserved.