Epitaxial growth of MOCVD-derived YBCO films by modulation of Cu（tmhd）2 concentration

• Published in: 稀有金属：英文版 no. 1; pp. 70 - 74
• Main Author: Jie Xiong Fei Zhang Xin Liu Rui-Peng Zhao Xiao-Hui Zhao Bo-Wan Tao
• Format: Journal Article
• Language: English
• Published: 2014
• Subjects: MOCVD; YBCO薄膜; 化学气相沉积法; 扫描电子显微镜; 生长浓度; 衍生; 调制; 铜
• ISSN: 1001-0521

Metal-organic chemical vapor deposition was applied to fabricate YBa2Cu3OT-a （YBCO） films on singlecrystal LaA103 （001） substrates for its high deposition rate, easy adjustment on film composition, and low requirement on vacuum apparatus. The effects of Cu（tmhd）2 concentra- tion in the precursor on the properties of YBCO films were systematically investigated. X-ray diffraction （XRD） reveals that the mole ratio of Cu/Ba in the precursor from 0.77 to 0.97 is helpful to improve the crystallization and out-of-plane orientation of YBCO films; however, it hardly affects the inplane texture. Scanning electron microscope （SEM） shows the dense, crack-free but rough surface, on which there are Cu-O and Ba-Cu-O outgrowths identified by energy-dispersive spectrometer （EDS）. As the mole ratio of Cu/Ba increasing, the average size of Ba-Cu-O precipitates keeps increasing and the film composition becomes inhomoge- neous at the mole ratio of Cu/Ba of 0.97. The 250 nm thick YBCO film prepared at the mole ratio of Cu/Ba of 0.91 shows the critical current density （Jc） of 4.0 MA.cm-2 （77 K, 0 T）.