Seeded growth of ZnO nanorods from NaOH solutions

Abstract

Perpendicularly aligned arrays of corrugated ZnO nanorods were grown onto gold patterned LiTaO 3 substrates, coated with a sputtered ZnO seed layer. During the growth process, these substrates were held submerged in an aqueous solution comprising a 1:40 mol ratio mix of zinc nitrate hexahydrate to sodium hydroxide. The substrates were placed in a custom apparatus residing in an autoclavable storage bottle. Scanning electron micrographs, which were taken at different deposition intervals, suggest that the growth mechanism of ZnO nanorods initiates with the etching of the ZnO sputtered seed layer into hexagonal bases (> 500 nm across), from where multiple protrusions (40 nm–100 nm in width) grow atop these hexagonal bases. Such nanoprotrusions later coalesce into larger nanorods. Uniformly distributed high density corrugated nanorods, with proximal spacing between adjacent nanorods of approximately 20 nm–50 nm, were observed over the entire surface.