Zn1-xMgxO thin films have been energetically deposited from a filtered catholic vacuum arc at moderate temperatures and microstructurally characterised. Partial oxidation ('poisoning) of the Zn0.8Mg0.2 cathode caused layering and phase separation in the films. However, periods of non-reactive ablation steps incorporated into the deposition process minimised the effects of cathode poisoning and enabled dense, phase-pure, wurtzite Zn1-xMgxO to be grown at room temperature and 200 degrees C. Elevated substrate temperature resulted in enlarged grains and increased surface roughness. Increased substrate bias caused reduced crystalline order. X-ray absorption spectra from the homogeneous Zn1-xMgxO films, revealing local atomic bonding, were similar to spectra from single crystal ZnO but with features indicative of defects related to oxygen deficiency. (C) 2014 Elsevier B.V. All rights reserved