ZnO nanowire-based antireflective coatings with double-nanotextured surfaces

Abstract

High-aspect-ratio nanotextured surfaces with different morphologies (straight, core shell type, and core branch type nanowires) are prepared by a hydrothermal method of ZnO nanowires, followed by means of RF sputtering for core shell type nanowires and e-beam evaporation for branch-type nanowires. The structural analysis showed that the MgO has highly preferred orientation along the < 111 > and < 200 > direction, respectively, and the crystalline continuity between the ZnO and MgO layers were also showed. Compared with ZnO nanowires, the MgO/ZnO samples drastically suppress broad and omnidirection reflection, which ascribes to the refractive-index modulation along the lateral direction of nanowires growth as well as the vertical direction. It was also shown that morphology could have a substantial influence on the antireflection property. These results suggest that double-nanotextured surface is one of the promising structures for antireflective surfaces without fine control in nanowire morphology.