Formation of highly crystallized ZnO nanostructures by hot-water treatment of etched Zn foils

The effects of surface oxidation of etched metallic Zn foils by hot-water treatment at 90 °C for 4, 8, 12 and 24 h were investigated. ZnO nanostructures consisting of nanowires and nanorods were obtained at different hot-water treatment times. The photoluminescence spectra of the as-formed ZnO nanostructures exhibit near band edge UV emission, indicating their good crystallinity. Further evidence of good crystallinity is the HR-TEM observations of the lattice fringes of wurtzite ZnO. Raman scattering of the ZnO nanostructures indicates that crystallinity is improved, and the number of oxygen vacancies is reduced at longer durations of hot-water treatment.

► Crystalline ZnO nanowires and nanorods formed by hot-water treating etched Zn foils.
► ZnO nanostructures formed by hot-water treatment show excellent photoluminescence.
► Optical properties and crystallinity improved with longer hot-water treatment.
► Rough nanorod surface formed after 24-h hot-water treatment because ZnO dissolved.