Morphology of Zn/Al layered double hydroxide nanosheets grown onto aluminum thin films

Layered double hydroxide (LDH) nanosheets have been fabricated by a one-step, room-temperature, hydrothermal process on sputtered-aluminum thin substrates, in which the metal substrate acts as both reactant and support. The morphology, dimensions and composition of the obtained nanostructures have been characterized as a function of the substrate thickness by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersion spectroscopy (EDS) and photoluminescence measurements. While the lateral size of the observed LDH nanosheets depends on the available aluminum, the stoichiometry does not change appreciably. Even for the lowest values of the aluminum thickness, the excess zinc does not alter the chemical composition of LDH, but rather produces ZnO nanorods that show the characteristic defect-related broad visible photoluminescence centered at approximately 600 nm. The results show that a controlled growth of Zn/Al LDH nanosheets can be achieved onto sputtered aluminum thin layers with thicknesses as low as 10 nm, which can be important for the integration of LDH on generic substrates.