ZnO/Zn2TiO4 composite nanostructures produced by laser ablation in air.

We report on the formation of three-dimensional nanostructures composed of nanoparticles by applying the technology of pulsed laser deposition in the air at atmospheric pressure. The depositions were performed by ablating targets synthesized of ZnO and TiO 2 in different ratios as initial materials. Our attention was focused on the structure and morphology, as well as on the optical and photoluminescent properties of the as-deposited structures. It was found that the structure of the samples represented a composite of ZnO and Zn 2 TiO 4 nanoparticles with different ratios between the phases depending on the initial materials. Although the samples consisted of nanoparticles of similar shape and size distribution, the ratio between the different crystal phases influences the morphology of the material deposited on the substrates. The samples' optical properties are strongly affected by their thickness since the accumulation of material led to the formation of strongly absorbing media. A small amount of Zn 2 TiO 4 nanoparticles introduced in the ZnO structure significantly changes the sample photoluminescence response, with the ratio between ultraviolet and visible emission significantly differing from that of the pure ZnO sample. A potential application of such composite structures as gas sensor elements was demonstrated. [Display omitted] • High porosity composite structures were fabricated by PLD in open air. • Composites consist of aggregated nanoparticles from ZnO and Zn 2 TiO 4. • ZnO/Zn 2 TiO 4 ratio determines the morphology and optical properties of the composite. • Zn 2 TiO 4 introduced in the ZnO structures had a significant effect on their PL. • Composite samples were used as a sensor element activated by UV light. [ABSTRACT FROM AUTHOR]