This chapter presents the effect of lanthanum (La) dopant on the structural and optical properties of the following ferroelectric thin films: barium strontium titanate (Ba0.5Sr0.5TiO3) (BST), lithium tantalate (LiTaO3), and lithium niobate (LiNbO3). We applied X‐ray diffraction, Fourier transform infrared spectroscopy (FTIR), and in some cases, atomic force microscopy to investigate the structural properties, functional groups, and particle size, as well surface roughness of these lanthanum‐doped thin films, respectively, whereas ultra violet‐visible (UV‐Bis) spectrometer was applied to investigate the optical bandgap of the La‐doped thin films. The results are in agreement with other previously researcher studies using different substrate materials. In general, the effect of La dopant highly affects both the structural and optical properties, changing significantly the grain size, surface roughness, and energy gap, and in certain cases, such as BST doped by La can change the material electric properties from insulator to semiconductor. Therefore, La‐doped thin films may offer promising applications in the future.
Part of the book: Rare Earth Element