Synthesis of Cu-ZnO and C-ZnO nanoneedle arrays on zinc foil by low temperature oxidation route: Effect of buffer layers on growth, optical and field emission properties

► The effect of different buffer layers has been studied on the optical and field emission properties. ► The buffer layer plays an important factor to control the growth process of the ZnO nanoneedles. ► The morphological studies show different density of ZnO nanoneedles.