Epitaxial growth mechanism of Pb(Zr,Ti)O₃ thin films on SrTiO₃ by chemical solution deposition via self-organized seed layer

Abstract

Using scanning transmission electron microscopy and electron energy loss spectroscopy, we have elucidated the local structure and the crystallization mechanism of amorphous phase PbZr x Ti 1¹x O 3 (PZT) (x = 0.3) thin films deposited on SrTiO 3 (STO) (001) single-crystal substrates by chemical solution deposition. The amorphous phase involves the short-range order of (Ti/Zr)O 6 octahedra and PbO, and then, they are connected with the residual carbon. During the pyrolysis process, the first unit cells of the film has already crystallized with cube-on-cube epitaxial relationship with the STO substrate. The filmsubstrate interface is coherent and atomically sharp between the first PbO layer and the substrate. In the crystallization process, this layer seems to act as a seed layer for PZT epitaxial film growth. It accelerates crystal growth as a nucleation site and simultaneously shrinks the film by combustion of the residual carbon and subsequent densification, affecting the local coordination structure in the amorphous phase. The self-organized seed layer in the pyrolyzed film appears to play an important role in the epitaxial growth.

Microstructure analysis of porous lead zirconate–titanate films

“…The presence of voids near the Pt–PZT interface inhibits mass transfer, reducing the nucleation and growth of Pe grains. In addition, Kiguchi et al 77 have shown that the presence of carbon stimulates PZT epitaxial growth. Thus, the presence of voids and carbon residuals at the Pt surface hinders nucleation and leads to the formation of large crystals.…”

Mechanical Switching of Ferroelectric Domains in 33‐200 nm‐Thick Sol‐Gel‐Grown PbZr0.2Ti0.8O3 Films Assisted by Nanocavities

“…Our results suggest that the ferroelectric domains, irrespective of the underlying mechanism responsible for their stability, are clamped in the volume of the layer, possibly by defects. Although the growth of PZT thin films by soft chemical methods like sol-gel is not very common, despite the advantage of it being an affordable synthesis process to coat large areas, the presence of nanoscale cavities has been reported recently in similar films grown by metalloorganic decomposition [31]. The low magnification STEM-HAADF images in Figure 1b and in Figure 8 show that films do have a large amount of such nanometer-size defects, the aforementioned cavities, which could favor the clamping of domains created by the flexoelectric effect, without the need to reach the bottom electrode.…”

Ferroelectric photovoltaic tensor in visible-light-active Fe-doped BaTiO3single crystals

“…11,12) The widespread usage of MLCCs more or less relies on the defect chemistry [13][14][15][16][17][18][19][20][21] established for SrTiO 3 and BaTiO 3 . At present, intensive efforts [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] have been made to explore nanostructured materials and devices using BaTiO 3 -based materials, whereas the deep understanding of defects is far from complete for Pb(Zr, Ti)O 3 , [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] (Bi, Na)TiO 3 , [54][55][56][57]…”