Influence of Cr dopant on the microstructure and optical properties of ZnO nanorods

One-dimensional (1D) undoped and Cr doped ZnO nanorods with average length of 1 µm and diameter of 80 nm were synthesized using hydrothermal method where a fast growth of ZnO nanorods on the seed layer was observed. Afterwards, the effects of Cr dopant on structural, surface morphology and optical properties of nanorods were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultra-violet visible (UV-Vis) spectroscopy. The results showed that ZnO has a wurtzite hexagonal structure and that the Cr atoms were well incorporated into the ZnO crystal structure. Moreover, it was found that the Cr atoms could facilitate the preferential growth of nanorods in C-axis. Also, it was concluded from optical properties that doped ZnO nanorods was so appropriate for photocatalytic applications because the optical band gap. For example, the calculated band gap of ZnO nanorod decreased from 3.12 eV for pure ZnO nanorods to about 2.41eV for 3 at. % Cr doped ZnO nanorods which is quite enough to be activated even at visible (550nm) light for photocatalyst aims.