Epitaxial Growth of Nd1.85Ce0.15CuO4 and BiFeO3 Thin Films

• Main Authors: Wan-TingChuang, 莊椀婷
• Other Authors: Xiao-Ding Qi
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/12380856089417516312

碩士 === 國立成功大學 === 材料科學及工程學系 === 104 === In this study, we attempted to grow epitaxial Nd1.85Ce0.15CuO4 (NCCO) film on the (001) SrTiO3 substrate as the bottom electrode for the growth of the multiferroic BiFeO3 (BFO) film. The NCCO and BFO targets used for the deposition were prepared by the solid state reaction method. Both the RF magnetron sputtering and pulsed laser deposition (PLD) methods were studied for the NCCO film growth, while the growth of BFO films was only attempted by the sputtering method. Various efforts were made in order to obtain the epitaxial NCCO films, including direct formation of the desired phase at the heated substrate, deposition at room temperature (RT) followed by the post-annealing at high temperature, and varying the target composition in favor of some elements. The optimal NCCO films were obtained with the PLD method, which were deposited at RT from a stoichiometric target and then annealed in air at 950 C for 2 hours. The films grown by such a PLD process were epitaxial and showed a full width at half maximum of 0.134。 in the X-ray diffraction (004) rocking curve. They had a pure phase and were absent of the secondary phase, Nd0.5Ce0.5O1.75, which was often observed in the NCCO films grown by the sputtering method. The electric measurement showed that the resistivity of the PLD grown NCCO films decreased as the temperature decreased, i.e. a metallic behavior, with the RT value being 8.163×10-2 Ω.cm, which is good enough as the electrode. Furthermore, the surface roughness of the PLD grown NCCO films was 1.53 nm, suitable for the subsequent growth of BFO. Attempts have been made to grow epitaxial BFO film on NCCO. The preliminary results were encouraging, which showed that (001) oriented BFO was able to grown on the (001) NCCO film surface.