Thickness Effect on (La_(0.26)Bi_(0.74))_2Ti_4O_(11) Thin-Film Composition and Electrical Properties

Highly oriented(00l)(La_(0.26)Bi_(0.74))_2Ti_4O_(11 )thin films are deposited on(100) SrTiO_(3 )substrates using the pulsed laser deposition technique.The grains form a texture of bar-like arrays along Sr Ti O_3110directions 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)_4Ti_3O_(12 )and TiO_(2 )components above a critical film thickness.Otherwise,the phase decomposes into the random mixture of Bi_2Ti_2O_(7 )and Bi_4Ti_3O_(4 )spherical grains in thinner films.The critical thickness can increase up to 440 nm as the films are deposited on LaNiO_3-buffered SrTiO_(3 )substrates.The electrical measurements show the dielectric enhancement of the multi-components,and comprehensive charge injection into interfacial traps between(La,Bi)_4Ti_3O_(12 )and TiO_(2 )components occurs under the application of a threshold voltage for the realization of high-charge storage.