Synthesis of oriented BiFeO3 thin films by chemical solution deposition: Phase, texture, and microstructural development

摘要

Textured, thin films of BiFeO3 (similar to 120 nm thickness) were synthesized by chemical solution deposition from a mixture of iron- and bismuth-2-methoxyethoxides on Si(100)/SiO2/TiO2/Pt substrates. The use of alkoxides ensured good homogeneity and a low degree of organics that further facilitated low crystallization temperatures. Crystalline films were according to x-ray diffraction already obtained at 480 degrees C. Precursor characteristics were investigated using thermogravimetry and differential scanning calorimetry, whereas phase purity, microstructure and film topography were examined by x-ray diffraction, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. A small (10%) Bi excess was found necessary to obtain dense, pore-free films. Such additions also prevented decomposition of BiFeO3 at high temperatures. The observed (012) texture is believed to originate from the growth mechanism as no relation to the substrate is found. This is also confirmed by observing (012) texture for films on glass substrates.