Effects of precursor solution pH value and substrate texture on orientation degree of sol-gel-derived bismuth titanate thin films

Abstract

The c-axis oriented Bi4Ti3O12 thin films were prepared on Si(100), Y-ZrO2(100), SrTiO3(100) crystal, (111)Pt/Ti/Si and quartz glass substrates by sol-gel processing with bismuth nitrate and titanium butoxide. Effects of the lattice structure of the substrates, the annealing temperature, and the pH value of the solution on the orientation degree of Bi4Ti3O12 thin films were investigated. The results showed that Bi4Ti3O12 thin films with pure perovskite phase were obtained by using a solution of pH 2.5-3.5. The reaction mechanism in the precursor solution and the formation mechanism of c-axis orientation perovskite phase of Bi4Ti3O12 thin films on various substrates were discussed. Completely c-axis oriented Bi4Ti3O12 thin film on SrTiO3(100) substrate and highly c-axis oriented Bi4Ti3O12 thin film on quartz glass substrate were acquired by using a solution of pH 3.5.