Fabrication of bismuth titanate (Bi4Ti3O12) thin lms: Effect of annealing temperature on their structural and optical properties

Bismuth titanate (Bi4Ti3O12) ceramics, so-called BiT, have many modern applications in microelectronics, sensors, and capacitors. In this study, the related solutions for fabricating BiT thin lms were prepared and, then, coated on glass substrates by using the sol-gel technique and the spin coating instrument. The X-ray diraction patterns of our samples indicated that the crystalline phases of the BiT were orthorhombic. Based on the transmission-spectra analysis, the samples are transparent in a visible spectrum, and their optical energy gaps were found to be 3.36 eV and 3.41 eV for the BiT thin lms annealed at 600C and 650C, respectively. Other physical quantities, such as refractive index, thickness, extinction coecient, and dielectric constant, were estimated by Swanepoel's method. The results show that as the annealing temperature rises, the real part of the dielectric constant becomes larger, that is, our samples are good dielectric materials.