Synthesis and characterization of self-assembled c-axis oriented Bi2Sr3Co2O(y) thin films by the sol-gel method.
Synthesis and characterization of self-assembled c-axis oriented Bi2Sr3Co2O(y) thin films by the sol-gel method.
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DOI：
10.1039/c0dt01731k
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发表时间：
2011-09
影响因子：
4
通讯作者：
Xuebin Zhu;Xianwu Tang;D. Shi;H. Jian;H. Lei;W. Yeoh;Bangchuan Zhao;Jie Yang;Qi Li;R. Zheng;S. Dou;Yuping Sun
中科院分区：
文献类型：
--
作者：
Xuebin Zhu;Xianwu Tang;D. Shi;H. Jian;H. Lei;W. Yeoh;Bangchuan Zhao;Jie Yang;Qi Li;R. Zheng;S. Dou;Yuping Sun
采用溶胶-凝胶法在SrTiO（3）（100）、（110）和（111）单晶衬底上制备了Bi（2）Sr（3）Co（2）O（y）薄膜。所有的薄膜都是c轴取向的，而不管衬底的取向，表明自组装c轴取向，和X射线光电子能谱的结果给出了证据的共存的Co（3+）和Co（2+）离子在衍生的薄膜。透射电子显微镜观察表明，所有样品都是c轴取向的，不同样品没有明显差异，并且c轴晶格常数被确定为约15 μ m，表明失配结构。建立了失配钴基薄膜自组装c轴取向的唯象热力学相图。由于Co（3+）/Co（2+）离子的共存，所有样品都表现出半导体性质，在SrTiO（3）（100），（110）和（111）上制备的薄膜在350 K时的电阻率分别为~47，39和17 mΩ cm，而在300 K时的塞贝克系数分别为97，89和77 μV K（-1）。Bi（2）Sr（3）Co（2）O（y）自组装薄膜的成功制备为研究失配结构复合氧化物薄膜的生长机制提供了有效的原型。
Bi(2)Sr(3)Co(2)O(y) thin films are prepared on SrTiO(3) (100), (110) and (111) single crystal substrates using the sol-gel method. All the thin films are c-axis oriented regardless of the orientation of the substrate suggesting self-assembled c-axis orientation, and X-ray photoelectron spectroscopy results give evidence of coexistence of Co(3+) and Co(2+) ions in the derived films. Transmission electronic microscopy observations reveal that all samples are c-axis oriented with no obvious differences for different samples, and the c-axis lattice constant is determined as ~15 Å suggesting the misfit structure. A phenomenological thermodynamic phase diagram for self-assembled c-axis orientation is established for misfit cobaltate-based films using chemical solution deposition. All samples behave like semiconductors due to the coexistence of Co(3+)/Co(2+) ions, and the resistivity at 350 K is ~47, 39 and 17 mΩ cm for the thin films on SrTiO(3) (100), (110) and (111), respectively, whereas the Seebeck coefficient at 300 K is 97, 89 and 77 μV K(-1). The successful attainment of Bi(2)Sr(3)Co(2)O(y) thin films with self-assembled c-axis orientation will provide an effective prototype for investigation of growth mechanisms in complex oxide thin films with a misfit structure.