Structural characterisation of energetically deposited Zn1−xMgxO films

Abstract

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°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.