Low-temperature growth of ZnO nanorods by chemical bath deposition

Aligned ZnO nanorod arrays were synthesized using a chemical bath deposition method at normal atmospheric pressure without any metal catalyst. A simple two-step process was developed for growing ZnO nanorods on a PET substrate at 90–95 °C. The ZnO seed precursor was prepared by a sol–gel reaction. ZnO nanorod arrays were fabricated on ZnO-seed-coated substrate. The ZnO seeds were indispensable for the aligned growth of ZnO nanorods. The ZnO nanorods had a length of 400–500 nm and a diameter of 25–50 nm. HR-TEM and XRD analysis confirmed that the ZnO nanorod is a single crystal with a wurtzite structure and its growth direction is [0001] (the c-axis). Photoluminescence measurements of ZnO nanorods revealed an intense ultraviolet peak at 378.3 nm (3.27 eV) at room temperature.

Graphical abstractFE-SEM images of aligned ZnO nanorods on PET substrate: (a) ZnO nanorods without seeds (plain view, low magnification); (b) ZnO nanorods with seeds (plain view, low magnification); (c) ZnO nanorods on seeds (cross-section). Nucleation of ZnO nanorod on ZnO seeds has a low free energy barrier of activation than on bare substrate. So, the ZnO seeds were indispensable for the aligned growth of ZnO nanorod.Figure optionsDownload full-size imageDownload as PowerPoint slide