Thickness Effect on (La0.26Bi0.74)2Ti4O11 Thin-Film Composition and Electrical Properties.

Highly oriented (00l) (La₀.26Bi_0.74)2Ti₄O₁₁ thin films are deposited on (100) SrTiO₃ substrates using the pulsed laser deposition technique. The grains form a texture of bar-like arrays along SrTiO₃ ⟨110⟩ directions for the film thickness above 350 nm, in contrast to spherical grains for the reduced film thickness below 220 nm. X-ray diffraction patterns show that the highly ordered bar-like grains are the ensemble of two lattice-matched monoclinic (La,Bi)₄Ti₃O₁₂ and TiO₂ components above a critical film thickness. Otherwise, the phase decomposes into the random mixture of Bi₂Ti₂O₇ and Bi₄Ti₃O₄ spherical grains in thinner films. The critical thickness can increase up to 440 nm as the films are deposited on LaNiO₃-buffered SrTiO₃ substrates. The electrical measurements show the dielectric enhancement of the multi-components, and comprehensive charge injection into interfacial traps between (La,Bi)₄Ti₃O₁₂ and TiO₂ components occurs under the application of a threshold voltage for the realization of high-charge storage. [ABSTRACT FROM AUTHOR]