Zinc/ZnO core–shell hexagonal nanodisk dendrites and their photoluminescence

We report the electrodeposition of novel zinc dendrites composed of self-assembled regular hexagonal zinc nanodisks shelled with ZnO layers. The Zn nanodisks range in diameter from about 100 nm to several hundreds of nanometers and are about 20–40 nm thick. The thickness of ZnO layer is about 3–4 nm. In the as-prepared condition, the photoluminescence (PL) spectra of the dendrites are composed of a violet emission band at about 415 nm and a green emission band at about 550 nm at room temperature. The violet and green emissions are attributed to the radiative recombination of a delocalized electron close to the conduction band with a deeply trapped hole in the VZn- and VO+ centers, respectively. The PL of the dendrites can be tuned by heat treatment. With an increase in the heating temperature, the intensity of the green emission increases, while the intensity of the violet emission decreases.