Flow modulation epitaxy of ZnO films on sapphire substrates

High-quality c-axis-oriented single crystal ZnO films have been grown successfully on sapphire substrates by the flow modulation epitaxy (FME) method using a commercial organometallic vapor phase epitaxy (OMVPE) reactor. Diethylzinc (DEZn) and nitrous oxide (N2O) were used as reactant gases. The growth of ZnO films has been conducted as a function of growth conditions, including temperature, growth rate and susceptor rotation rate. A growth rate as high as 2 μm/h was achieved at 500 °C, which is comparable to typical OMVPE technology. Films showed excellent alignment with the substrate both along the c-axis, and in the growth plane, and root mean square surface roughness values as low as 1.9 nm.