Preparation And Characterization Of Bismuth Titanate Based Pseudo-Perovskite Structure Thin Films

Perovskite oxide thin films have attracted great interest for their potential and wide applications in microelectronic, optoelectronic and semiconductor devices. In this dessertation, preparation and structures and surface microstructure of thin films have been investigated. Investigations on optical properties of pure and doped perovskite thin fims have also been carried out. The reseach work and experimental results are as follows: 1. LaNiO3 (LNO) thin films have been prepared on Si(100) substrates by Solution Chemistry Decomposition (SCD) . The effect of pyrolysis temperature, times and thickness of LaNiO3 on preperties of LaNiO3/Si were investigated. The orientation of all thin films is (110); especialy the thin film heat treatment six times by 650°C has the maximum orientation. The comparatively (110) orientation parameter of LNO thin film is 2.05. 2. The effect of preperation of precursor solutions on properties of Bi4Ti3O12 has been investigated. The process of preparing the Bi4Ti3O12 ferroelectric thin films was improved. 3. The effect of heat treatment on structure of Bi4Ti3O12 thin films grown on Si(100) substrates derived from sol-gel process has been investigated. The Bi4Ti3O12 thin films annealed at lower temperature have (117) preferred orientation, while annealed at higher temperature have random orientation. The preferred orientation of BTO thin films can be controlled by varying the parameters of the processing. 4. The optical properties of Bi4Ti3O12 thin films have been studied by optical transmittance spectrum. The dispersion properties of refractive index and extinction coefficient are elucidated according to Chauchy formula, the optical band gap is 3.69 eV. 5. The effect of heat treatment on structure of Bi3.25La0.75Ti3O12 (BLT) thin films grown on Si(100) substrates derived from sol-gel process has been investigated. The BLT thin films annealed at lower temperature have (117) preferred orientation, while annealed at higher temperature have (001) preferred orientation. This can be explained by considering lattice mismatch and thermal stress between BLT thin films and Si substrates. 6. The effect of heat treatment on properties of BLT thin films grown on quartz substrates derived from sol-gel process has been investigated. The dispersion properties of refractive index are elucidated according to Chauchy formula. Refractive index and optical band decreasing as the heat treatment temperature increasing. 7. The effect of thickness of BLT thin films on optical properties of BLT thin films has been studied by optical transmittance spectrum. The dispersion properties of refractive index are elucidated according to Chauchy formula. Refractive index and optical band gap decreasing as the thickness increasing.