Feasibility of ZnO and Zn Seed Layers for Growth of Vertically Aligned and High-Quality ZnO Nanorods by the Sonochemical Method

Abstract

The distinct roles of zinc oxide (ZnO) and zinc (Zn) seed layers in the growth of vertically aligned high-quality zinc oxide (ZnO) nanorods by the sonochemical method were investigated. ZnO nanorods were grown on p-type Si (111) with {Ti (10 nm)/ZnO (85 nm)}, {ZnO (85 nm)}, {Ti (10 nm)/Zn (55 nm)} and {Zn (55 nm)}. Ti (10 nm) was incorporated as the buffer layer. All depositions were carried out using RF-sputtering. The effects of the seed layers on the growth of vertically aligned high-quality ZnO nanorods (NRs) were systematically studied using Xray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive Xray (EDX) analysis and transmission electron microscopy (TEM). The results indicated that the ZnO nanorods synthesized using ZnO (85 nm) as seed layer, with and without the Ti buffer layer, have better average aspect ratio than those synthesized using Zn (55 nm) as seed layer. Therefore, ZnO serves as a potential and preferable seed layer for the synthesis of vertically aligned highquality ZnO nanorods with lower compressive strains. Furthermore, the lattice mismatch between ZnO nanorods, seed layer and Si substrates was reduced with the introduction of thin Ti (10 nm) as a buffer layer. In general, the type and thickness of seed layer are key parameters to synthesize high quality ZnO nanorods