ZnO/Zn2TiO4 composite nanostructures produced by laser ablation in air
Anna Dikovska, Ru Nikov, Georgi Avdeev, Genoveva Atanasova, Tina Dilova, Daniela Karashanova, Nikolay Nedyalkov
Abstract
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 TiO2 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 Zn2TiO4 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 Zn2TiO4 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.