Crystalline texture analyses of sputtered BiFeO3 thick films on Si with a large polarization

In our work last year (H. Zhu et al., Rhombohedral BiFeO3 thick films integrated on Si with a giant electric polarization and prominent piezoelectricity, Acta Materialia 200 (2020) 305-314), it was demonstrated that the rhombohedral-like, (110)-textured BiFeO3 thick films (similar to 2 mu m) sputter-deposited at 450 degrees C and 500 degrees C exhibited ultrahigh polarizations of P-r similar to 115 mu C/cm(2) and 135 mu C/cm(2), respectively. However, it is not sufficient to explain these ultra-high polarizations by a preferential growth mechanism and the effect of a moderate compressive strain. To further clarify the polarization enhancement of the films, the texture characteristics of these BFO thick films were quantitatively analyzed by fitting the rocking curves and pole figures to the March-Dollase model. The results showed that, in addition to the (110)-textured growth of a BFO thick film under a moderate compressive strain, the minority non-(110)-textured grains also contributed to the enhancement of the total polarization. Our study demonstrates that, the ultra-high polarizations of our BFO thick films can be well explained by adding the contribution from non-textured grains to the preferential growth of the film under a compressive strain.

Automated summary

By quantitatively analyzing the texture characteristics of the rhombohedral BiFeO3 thick films and adding the contribution from non-textured grains to the preferential growth under compressive strain, the study further explains the ultra-high polarizations of the films.