Microstructure development of BiFeO3-PbTiO3 films deposited by pulsed laser deposition on platinum substrates
Microstructure development of BiFeO3-PbTiO3 films deposited by pulsed laser deposition on platinum substrates
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DOI：
10.1016/j.actamat.2013.11.043
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发表时间：
2014-03-01
期刊：
影响因子：
9.4
通讯作者：
Bell, Andrew J.
中科院分区：
文献类型：
--
作者：
Esat, Faye;Comyn, Tim P.;Bell, Andrew J.
采用脉冲激光沉积法在多晶Pt/TiOx/SiO2/Si衬底上制备了BiFeO 3-PbTiO 3薄膜。X射线衍射分析表明，0.6BiFeO（3）-0.4PbTiO（3）薄膜由于与衬底的晶格匹配，具有（001）择优取向。由于衬底膜界面处的晶格失配以及衬底和沉积膜的热膨胀系数的差异，衬底膜界面处的失配应变通过从（001）到（100）的类似于19%的取向转变而减轻。0.7BiFeO（3）-0.3PbTiO（3）薄膜为混合相菱面体-四面体结构，具有（001/（111））择优取向，这是由于薄膜与底层铂的（111）和（100）晶格相匹配以及接近准同型相界。不一致的结构和电性能的报道BiFeO 3-PbTiO 3薄膜的薄膜形态和扩散到铂铋解释。低于类似于220 nm厚度的膜由于Volmer Weber生长机制而产生短路，这导致膜内的物理缺陷。高于该临界厚度的膜还产生可变的电性能，这是由于铋扩散到下面的铂电极中，这已经通过能量色散X射线光谱法证实。
BiFeO3-PbTiO3 films around the morphotropic phase boundary were deposited by pulsed laser deposition on polycrystalline Pt/TiOx/SiO2/Si substrates. X-ray analysis confirms that 0.6BiFeO(3)-0.4PbTiO(3) films are (001) tetragonal preferentially orientated due to lattice matching with the underlying substrate. The misfit strain at the substrate film interface is relieved by a similar to 19% orientation transformation from (001) to (100) due to the lattice mismatch at the substrate film interface and the difference in thermal expansion coefficients of the substrate and deposited film. 0.7BiFeO(3)-0.3PbTiO(3) films are mixed-phase rhombohedral-tetragonal with (001/(111) preferential orientation due to the lattice match to the (111) and (100) of the underlying platinum as well as to being close to the morphotropic phase boundary. Inconsistent structural and electrical properties in reported BiFeO3-PbTiO3 films are explained in terms of film morphology and diffusion of bismuth into platinum. Films below similar to 220 nm thickness produce short circuits due to a Volmer Weber growth mechanism which results in physical defects within the films. Films above this critical thickness also produce variable electrical properties due to diffusion of bismuth into the underlying platinum electrode which has been confirmed by energy dispersive X-ray spectroscopy.