The effect of lanthanum (La3+) addition on the fabrication of Ba0.90La0.10TiO3 and Ba0.85La0.15TiO3

Abstract

• The addition of La 3+ caused crystallite size and grain size to decrease from BaTiO. • The addition of La 3+ on BaTiO 3 can decrease band gap energy. • Ba 1-x La x TiO 3 had response to the light and the photovoltaic effect The fabrication of Barium Titanate with the Lanthanum addition (Ba 1-x La x TiO 3 ) were prepared by using Chemical Solution Deposition (CSD) method. The addition of La 3+ were 10% and 15% on 0.5 M solubility. Spin coater was used in deposition process of thin films with speed 4000 rpm for 30 s. The sandwich-structured of Ba 1-x La x TiO 3 thin films were grown on a quartz substrate. Thin films were annealed at 850 °C with holding time of 1,5 h. X-Ray Diffraction (XRD) analysis showed the formation of tetragonal crystal (ICDD data base PDF # 831880). The addition of La 3+ caused crystallite size to decrease from BaTiO 3 . The crystallite size of BaTiO 3, Ba 0.90 La 0.10 TiO 3 and Ba 0.85 La 0.15 TiO 3 were 24 nm; 19 nm; 13 nm respectively. It is proportional to diffraction intensity values. The morphology of thin film was obtained from Scanning Electron Microscopy (SEM) characterization. The average of film thickness was 404 nm. The result of UV–Vis characterization showed that the addition of La 3+ increased the transmittance values at absorption edge area. The optical band gap was calculated and the values found for BaTiO 3, Ba 0.90 La 0.10 TiO 3 and Ba 0.85 La 0.15 TiO 3 were about 3.3 eV; 3.125 eV; and 3.125 eV respectively. Therefore, it could be concluded that the addition of La 3+ on BaTiO 3 can decrease band gap energy. The result of I-V characterization showed that Ba 1-x La x TiO 3 thin films had a response to the light and the photovoltaic effect under illumination 1000 W/m 2 .