Growth and interconversion of ZnO nanostructure films on different substrates

Hexagonal c-axis oriented ZnO nanorod (NR) arrays were grown on ZnO-coated glass substrates by chemical bath deposition (CBD). By varying the concentration of the precursor solutions, NRs' mean diameter was controlled from about 100-400 nm. With increasing the growing time, the morphology of as-synthesized ZnO NRs evolved: the top center of the ZnO NRs was eroded into volcano-like structures which developed into ZnO nanotubes (NT) and finally the ZnO NTs split to form ZnO nanosheets (NS). We have also introduced Al to the fabrication of some different ZnO nanostructures: on Al substrate, freestanding ZnO NSs formed a flower-like structure at the early growing period and these ZnO NSs reassembled into ZnO NTs as growing time increased; while on ZnO-coated glass substrate with an Al foil dipped in the growing precursor solution ZnO NR-NS composited arrays were synthesized.