Structure, Microstructure, and Dielectric Response of Polycrystalline Sr1-xZnxTiO3 Thin Films

In a view of the research interest in the high-permittivity materials, continuous enhancement of the dielectric permittivity epsilon ' with Zn content was reported for conventionally prepared Sr1-xZnxTiO3 ceramics with x up to 0.009, limited by the solubility of Zn on Sr site. Here, we use a sol-gel technique and a relatively low annealing temperature of 750 degrees C to prepare monophasic Sr1-xZnxTiO3 thin films with higher x of 0.01, 0.05, and 0.10 on Pt/TiO2/SiO2/Si substrates. The incorporation of Zn on the Sr site is confirmed by the decrease of the lattice parameter, while the presence of Zn in the films is proven by energy dispersive spectroscopy. The film thickness is found to be similar to 330 nm by scanning electron microscopy, while the average grain size of 86-145 nm and roughness of 0.88-2.58 nm are defined using atomic force microscopy. epsilon ' measured on the films down to 10 K shows a decreasing trend with Zn content in contrast to that for weakly doped Sr1-xZnxTiO3 ceramics. At the same time, the temperature dependence of the dissipation factor tan delta reveals a peak, which intensity and temperature increase with Zn content.

Automated summary

Monophasic Sr1-xZnxTiO3 thin films with higher Zn content of 0.01, 0.05, and 0.10 were prepared on Pt/TiO2/SiO2/Si substrates using the sol-gel technique at a relatively low annealing temperature. The presence of Zn on the Sr site was confirmed by a decrease in lattice parameter, and its presence in the films was proven by energy dispersive spectroscopy. The films had a thickness of approximately 330 nm and showed an average grain size of 86-145 nm and roughness of 0.88-2.58 nm as determined by scanning electron microscopy and atomic force microscopy. The dielectric permittivity epsilon' of the films decreased with increasing Zn content, contrary to weakly doped Sr1-xZnxTiO3 ceramics. Simultaneously, the dissipation factor tan delta showed a peak with increasing Zn content, with both intensity and temperature of the peak increasing.