Optical properties of epitaxial BiFeO3 thin films grown on LaAlO3
Optical properties of epitaxial BiFeO3 thin films grown on LaAlO3
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DOI：
10.1063/1.4905443
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发表时间：
2015-01-05
影响因子：
4
通讯作者：
Alexe, Marin
中科院分区：
文献类型：
--
作者：
Himcinschi, Cameliu;Bhatnagar, Akash;Alexe, Marin
分别在LaAlO3和TbScO3衬底上制备了高应变、近赝晶的BiFeO3外延薄膜。的对称性的四方形的BiFeO 3膜的偏振相关的拉曼测量的基础上进行了讨论，并与拉曼光谱测量的菱形薄膜沉积在TbScO 3的比较。椭圆偏振光谱的评价表明，沉积在LaAlO3上的薄膜是光学不太致密，在复杂的介电函数的功能是蓝移了0.3 eV的菱形膜相比。光学带隙为3.10 eV和2.80 eV的薄膜沉积在LaAlO3和TbScO3，分别确定。光学带隙和介电函数的偏移对于较厚的膜也几乎保持不变，这表明即使在厚度大于100 nm的膜中也保留了压缩应变，这也通过XRD研究证实。(C)2015 AIP Publishing LLC.
Highly strained and nearly pseudomorphic BiFeO3 epitaxial films were deposited on LaAlO3 and TbScO3 substrates, respectively. The symmetry of the tetragonal-like BiFeO3 films is discussed based on polarisation dependent Raman measurements and on the comparison with Raman spectra measured for rhombohedral films deposited on TbScO3. The evaluation of ellipsometric spectra reveals that the films deposited on LaAlO3 are optically less dense and the features in complex dielectric function are blue-shifted by 0.3 eV as compared to the rhombohedral films. Optical bandgaps of 3.10 eV and 2.80 eV were determined for the films deposited on LaAlO3 and TbScO3, respectively. The shift in the optical bandgap and dielectric function is nearly preserved also for thicker films, which indicates that the compressive strain is retained even in films with thicknesses above 100 nm as was confirmed also by XRD investigations. (C) 2015 AIP Publishing LLC.