Epitaxial growth of self-arranged periodic ZnO nanostructures on sapphire substrates grown by MOCVD

Abstract: This article reports an investigation on the growth behaviour of ZnO epitaxial nanostructures and thin films grown by metalorganic chemical vapour deposition (MOCVD). Self-arranged periodic ZnO nanostructures consisting of a large number of ZnO nano-columns can be directly grown on bare sapphire surface without any lithography or other pre-patterning processes. The spacing of periodic nanostructures was ∼117nm. The measurements of XRD 2θ/ω and φ scans indicated that epitaxial and non-epitaxial ZnO grains coexisted on the same substrate. According to cross-sectional transmission electron microscopy observation, these periodic ZnO nanostructures were epitaxially grown on sapphire substrates and separated by non-epitaxial ZnO grains. However, the in-plane periodic arrangement of ZnO nanostructures disappeared while increasing the growth temperature. Initial sapphire surface structure and CVD growth kinetics closely relate to the growth of self-arranged periodic ZnO nanostructures. [ABSTRACT FROM AUTHOR]