Surface Passivated Zinc Oxide (ZnO) Nanorods by Atomic Layer Deposition of Ultrathin ZnO Layers for Energy Device Applications

Chemically stoichiometric and electrically low-resistive high-quality zinc oxide (ZnO) nanostructures have been developed by surface passivation with atomic layer deposited ZnO layers. The impacts of homogeneous ZnO layer growth and its thickness on the physical properties ZnO nanorods were investigated. Vertically aligned ZnO nanorod structures were synthesized by two-step process, and the surface passivation was performed by atomic layer deposition ZnO at low temperatures. Surface passivated ZnO nanorods exhibit excellent improvement in crystallinity, chemical stoichiometry, optical, and electrical properties. Further, the surface passivated structures show significant enhancement in water-oxidation performance (nearly 3 orders of magnitude, i.e., μA → mA) with greatly reduced overpotentials. These investigations emphasize that surface passivation of hydrothermally grown ZnO nanostructures with the homogeneous materials can significantly enhance the structural and optical quality along with their device performance.