Growth of ZnO nano-rods and its photoconductive characteristics on the photo-catalytic properties

Abstract

Zinc oxide (ZnO) nano-rods has widely been investigated as a promising material for photo-catalysis, due to its high photocatalytic activity for the ambient gas molecules. Well-aligned ZnO nano-rods arrays were obtained by the two steps growth. Firstly, seeding layer deposition by RF magnetron sputtering, and secondly, nano-rods growth by hydrothermal processes were investigated. Moreover, after the samples were annealed at 450 ºC, these samples were compared in crystalline characteristics and photo-electronic characteristics. The morphology of grown ZnO nano-rods were observed as the hexagonal nano-rods and XRD shows a (002) orientation in wurtzite crystals structure. Annealing processes shows a remarkable improvement of crystallinity. PL measurements showed a steep band edge emission and broad defect states emission and also fairly improvement in crystalline properties by the annealing process. The photoconductivity measurement could lead to investigate the photo-catalytic phenomena on the surface of ZnO nano-rods against the environmental gas molecules. The annealed samples showed a higher photo-conductivity and surface activity for the oxygen gas molecules comparing to the as grown samples.