Development of a wet chemical method for the synthesis of arrayed ZnO nanorods

A two-step wet chemical process with economic and practical advantages was developed to prepare arrayed ZnO nanorods on glass substrates using zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O, ZnAc ₂) and monoethanolamine (NH₂CH₂CH ₂OH, MEA) as raw materials. The proposed method includes the predeposition of a thin ZnO seed layer using the solgel technique and the subsequent hydrothermal growth of ZnO nanorods at 130 ?C for 2 or 4 h. The synthesis process was monitored using X-ray diffraction (XRD), Fourier transformation infrared (FTIR) spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ZnO nanorods exhibited a diameter of 2575nm with an aspect ratio ranging from 10 to 50 after growing for 4 h. Each ZnO nanorod was confirmed to be a single crystal with a wurtzite structure and grow along the [0002] direction during the hydrothermal process. Photoluminescence (PL) measurements confirmed that the ZnO nanorods exhibited a near-UV emission at ∼380nm together with a green emission that was centered at ∼500 nm. We note that the PL properties may be affected by the hydrothermal time.