Preparation And Research Of ZnO Nanorod Arrays

Zinc oxide(ZnO) is an important direct band gap semiconductor material, with a band gap of3.37eV and large exciton binding energy of60meV at room temperature. It also is multifunction oxide material and has many applications such as transparent conductive coating, UV laser devices, solar cells, thermal and pressure sensitive device. ZnO is abundant on earth, relatively inexpensive and more importantly, it is environmentally-friendly material, would not result in pollution problems, and thus gradually become a research focus.Well-aligned ZnO nanorod array are an issue in the research of ZnO, it could be used in solar cells, electrochemical sensors and Nano-UV laser et al. It can be grown using the following methods:thermal evaporation, chemical vapor deposition, molecular beam epitaxy, magnetron sputtering and chemical bath deposition et al. Among all the methods, the chemical bath deposition method attracts most attentions for it could be used in non-vacuum environment closed to the room temperature, and its superiority to realize the large-scale growth of ZnO. But it is difficult to prepare the ZnO nanorod array on the substrate directly by chemical bath deposition for the lattice mismatch between the ZnO and the substrate, so many researchers prepared a thin layer of ZnO seed to reduce the mismatch rate by thermal evaporation and molecular beam epitaxy et al. In this case, the preparation of the seed layer which is really a complex process, limits the research of ZnO nanorod array.ZnO seed layer was prepared by a novel method named pre-heated treatment in this article, followed by chemical bath to finish the growth of ZnO nanorod array. This method did not require strict control of the experiment conditions and sophisticated equipment. The seed layer was affected by the pre-heated temperature and the concentration of the seed solution The sample was characterized by SEM, XRD and PL, and the results indicated that the prepared ZnO nanorod array was grown vertically on the substrate, and it was single crystal, wurtzite structure, and c-axis oriented.The influences of the parameters such as growing time, temperature, concentration and annealing temperature in the process of the chemical bath to the morphology and structure of the sample were discussed. Li was used as dopant to study the photo luminescence of the prepared ZnO nanorod array, the final results showed that the intensity of peak in the visible light region could be tuned by the doping concentration of the lithium element.