Preparation and Optical Properties of ZnO Nanocrystals by Chemical Bath Deposition

Abstract

ZnO nanocrystals were prepared using three different salts of ZnSO4, Zn (CH3COO)2and Zn (NO3)2by chemical bath deposition. The samples were characterized by XRD, SEM, PL, and FTIR spectroscopy. The XRD results showed that all the samples exhibit the hexagonal wurtzite standard crystal of ZnO. When the zinc precursor is ZnSO4and Zn (CH3COO)2, B1 and A2 possess the best crystallinity. The FESEM results showed all the samples have flower-like ZnO structures with difference grain size distributions, diameters and tips of the ZnO nanoneedles or nanorods. In the photoluminescence spectrum, we can observe that, all the samples have a very strong at the wavelengths from 475 to 650 nm, corresponding to relatively broad visible emission peak attributed to the oxygen defects. The experimental results of the sample prepared by ZnSO4exhibit the highest visible luminescent performance. In the infrared absorption spectrum, the band of all the ZnO powders was located at about 500 cm-1, which was the characteristic absorption peak of Zn-O bond. The stretching vibration peak of C=O can be observed at about 1700 cm-1. Meanwhile, there is a strong absorption of the hydroxyl groups in/on Zn (OH)2at around 3450 cm-1, which were from the water molecules.