Highly uniform, straightforward, controllable fabrication of copper nano-objects via artificial nucleation-assisted electrodeposition

Abstract

• Artificial nuclei achieve a highly uniform electrodeposition of Cu inside nanopores. • Tens nanometer-scaled Ni particle plays a role of an artificial nucleus. • High reproducibility of Cu electrodeposition into nanopores is attained over a large area. • Precise control of the geometry of Cu nano-objects is demonstrated. Electrochemical synthetic routes to sophisticated nanoobjects have been considered promising and reliable strategies for diverse purposes in a wide range of applications. In particular, electrodeposition using nanoporous templates has attracted intensive research interest due to the potential for realizing diverse nanostructures and delicate composition control of the resulting fabricated materials. Unfortunately, the electrochemical filling of nanomaterials into nanoporous templates still suffers from unexpected nonuniform formation of nanoobjects, originating from random nucleation in each nanopore and overgrowth from only a few nanopores. Here, we present a highly uniform, straightforward and controllable fabrication of Cu nanoobjects via an artificial nucleation-assisted electrodeposition principle using nanoporous AAO templates. Pre-electrodeposited Ni nanoparticles at the bottom of the nanopores of AAO successfully acted as nuclei at the early stage of the Cu electrodeposition process. The artificial nuclei enable highly uniform and stable Cu electrodeposition inside the nanopores of AAO templates by effectively suppressing the random overgrowth of Cu. By taking advantage of the stable electrodeposition behaviour, we demonstrate precise control of the geometry of Cu nanoobjects, uniformly dispersed over whole surfaces of substrates.