Seeded Epitaxial Growth of PbTiO_3 Thin Films on (001) LaAlO_3 using the Chemical Solution Deposition Method
Seeded Epitaxial Growth of PbTiO_3 Thin Films on (001) LaAlO_3 using the Chemical Solution Deposition Method
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(001) LaAlO_3 上化学溶液沉积法晶种外延生长 PbTiO_3 薄膜
DOI：
10.1557/proc-493-323
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发表时间：
1999
影响因子：
2.7
通讯作者：
F. Lange
中科院分区：
文献类型：
--
作者：
J. Kim;F. Lange
采用旋涂Pb-Ti双醇盐前驱体溶液的方法，在（001）LaAlO_3（LAO）衬底上外延生长了PbTiO_3（PTO）薄膜。在第一步中，通过用前体溶液的非常薄的层涂覆基底并热处理至800 °C持续1小时，用PTO的外延岛预沉积基底。孤立岛的外延取向关系为[100]（001）_PTO|| [100]（001）_老挝人民民主共和国。在第二步骤中，通过旋涂沉积另一PTO薄膜，以经由从籽晶岛的晶粒生长产生外延膜。通过X射线衍射、扫描电子显微镜、原子力显微镜和透射电子显微镜（TEM）表征了400至800 °C加热期间的外延序列。将该序列与LAO基底未接种的情况进行比较。无论衬底是否被接种，钙钛矿PTO晶粒在热解的无定形膜内成核和生长。生长在无籽晶衬底上的薄膜充其量只是高度织构化的多晶薄膜。TEM观察结果表明，只有少量的外延核形成在衬底/膜界面处，显然是由于与PTO和LAO之间的大晶格失配（~4%）相关的大应变能。在非晶膜内成核的其他未取向的PTO晶粒没有被消耗，因为外延晶粒随着温度的升高而变大。另一方面，当通过首先形成籽晶衬底来增加外延核的数量密度时，可以产生良好的外延膜。
Epitaxial PbTiO_3 (PTO) thin films were grown on (001) LaAlO_3 (LAO) substrates by a preseeded, two-step process via spin coating a Pb–Ti double alkoxide precursor solution. In the first step, a substrate was preseeded with epitaxial islands of PTO by coating the substrate with a very thin layer of the precursor solution and heat treating to 800 °C for 1 h. The isolated islands had an epitaxial orientation relationship of [100] (001)_PTO || [100] (001)_LAO. In the second step, another PTO thin film was deposited by spin coating to produce an epitaxial film via grain growth from the seeded islands. The sequence of epitaxy during heating between 400 and 800 °C was characterized by x-ray diffraction, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy (TEM). This sequence was compared to the case where the LAO substrate was not seeded. Regardless of whether the substrate was seeded or not, perovskite PTO grains nucleated and grew within the pyrolyzed, amorphous film. Films grown on the unseeded substrates were, at best, only highly textured, polycrystalline films. TEM observations showed that only a low number of epitaxial nuclei formed at the substrate/film interface due, apparently, to the large strain energy associated with the large lattice mismatch (~4%) between PTO and LAO. Other, unoriented, PTO grains that nucleated within the amorphous film were not consumed as the epitaxial grains grew larger with increasing temperature. On the other hand, good epitaxial films could be produced when the number density of epitaxial nuclei was increased by first forming a seeded substrate.