Cubic (Mg,Zn)O nanowire growth using catalyst-driven molecular beam epitaxy

We report on the growth of Mg-rich cubic (Mg,Zn)O nanowires using a catalysis-driven molecular-beam-epitaxy method. Nanowires were grown on both Si and Al₂O₃ substrates coated with a nominally 2-nm-thick layer of Ag. The (Mg,Zn)O nanowires were grown with a Zn and Mg cation flux, with an O₂/O₃ mixture serving as the oxidizing species. The growth temperature was 400 °C. Under these conditions, nanowires were observed to grow on the Ag sites. The nanowire diameter was on the order of 90 nm. (Mg,Zn)O nanowires as long as 2 μm were realized. High-resolution transmission electron microscope imagery shows the nanowires had single-phase cubic rock salt structure (Mg,Zn)O with a growth direction along the [100]. The presence and compositional distribution of Mg and Zn in the single nanowire were confirmed using a compositional line-scan, profiled across the nanowire, by energy dispersive spectrometry with scanning transmission electron microscopy.