With the development of industry, both the levels of environmental pollution and the production of organic pollutants have been strongly increased. In the current course of materials physics, research into functional materials that may have an environmental utility is a prominent and particularly important field. ZnO have been extensively investigated during many years due to their application in optoelectronics. The doping feasibility of this material widens the range of applications. In recent years, its capability as photocatalyst and gas sensor has also been explored.

In this work, nano- and microstructures of ZnO doped with Ni and Ag have been grown by a Vapour-Solid Method. Mixtures of ZnS and Ni, NiO or AgNO3, respectively, have been used as precursors. After the thermal treatments, a high number of elongated structures are observed (Figure 1). Depending on the precursor, nanoneedles (ZnS+Ni), nanocomobs and nanoneedles (ZnS+NiO) or hexagonal nanorods (ZnS+AgNO3) are obtained. A complete characterization of structural, morphological, compositional and luminescence properties have been carried out. For this purpose, several techniques based in both Scanning Electron Microscopy (SEM) and confocal microscopy have been used. X ray diffraction (XRD) and µ- Raman spectroscopy indicate that the structures grow in the typical wurtzite structure of ZnO showing good crystallinity. Incorporation of dopants has been investigated by X-Ray spectroscopy (EDS), the amount of Ni and Ag are homogeneous along the structures. Both cathodoluminescence (CL) and µ-photoluminescence (µ-PL) have been performed. The spectra show two main luminescence bands, the near band edge centred at about 3.26 eV, and a wide deep level band where several components with different relative intensities are observed depending on the type of dopant.