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C-axis textured thin films of gallium-doped indium zinc oxide (GIZO) with a 2% ratio of Ga/Zn, were obtained via RF-magnetron sputtering with high transparency and electrical conductivity. A Box-Behnken response surface design was used to evaluate the effects of the deposition parameters (InO target power, deposition time, and substrate temperature) on the chemical composition, optical, electrical, and structural properties of the GIZO films. The optical constants and the electrical properties were obtained using optical models. The GIZO stoichiometry, and therefore the In/Zn atomic ratio, affected the crystallinity, crystalline parameters, band gap, and charge carrier mobility of the GIZO films. The charge carrier density was related to the change in the crystalline parameters of the hexagonal structure and the In/Zn atomic ratio. The best electrical conductivity values (1.75 × 10 Ω cm) were obtained for GIZO films with In/Zn ratio ≥ 1. Several figures of merit (FOM) defined for the visible and solar regions were comparatively used to select the optimal In/Zn atomic ratio that provided the best balance between the conductivity and the transparency. The optimal In/Zn ratio was in a range of 0.85–0.90 for the GIZO films., This work was supported by projects RNM1399 and TEC 2014-53906-R, Junta de Andalucía and Ministry of Economy and Competitiveness of Spain respectively. The authors are grateful to CSIC (Comisión Sectorial de Investigación Científica) of the Universidad de la República, in Montevideo, Uruguay, PEDECIBA- Física, ANII (Agencia Nacional de Investigación e Innovación), Uruguay; and to SCAI –Unidad de Nanotecnología of the University of Malaga. DII of PUCV (Pontifical Catholic University of Valparaiso) of Chile and FODECYT of Chile Grant no. 1160485, Chile, are also acknowledged.

We report on the magnetic and structural properties of Co-doped ZnO nanoparticles prepared by the vaporization-condensation method in a solar reactor. X-ray diffraction data and high-resolution electron microscopy (HREM) confirm the total absence of metallic Co clusters or any other phase different from wurtzite-type ZnO. Electron energy loss spectroscopy analyses performed on several particles indicate that the oxidation state of Co is +2 and yield an average Co concentration of 4.5at.%, in good agreement with the nominal composition. Transmission electron microscopy micrographs show that shape and size of the particles are strongly dependent on the preparation conditions, as well as the microstructure as evidenced by HREM. Ferromagnetism is only found in samples prepared in vacuum revealing a close correlation between microstructure and magnetic properties.