Shape transitions of epitaxial islands during strained layer growth: anatase TiO2(001) on SrTiO3(001).
Shape transitions of epitaxial islands during strained layer growth: anatase TiO2(001) on SrTiO3(001).
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DOI：
10.1103/physrevlett.102.146102
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发表时间：
2009-04
影响因子：
8.6
通讯作者：
M. Marshall;M. R. Castell
中科院分区：
文献类型：
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作者：
M. Marshall;M. R. Castell
超高真空下的长时间退火使钛酸锶(001)的表面区富含二氧化钛，形成锐钛矿型二氧化钛(001)的外延岛。用超高真空扫描电子显微镜(SEM)研究了生长过程中失配应变引起的形貌变化。从正方形岛屿开始，观察到两种类型的形状转变。在第一幅图中，在1000到1030摄氏度之间，锐钛矿岛在长度上拉长，在宽度上变窄。这种生长行为遵循特罗夫-特罗普模型[Phys.莱特牧师。70,2782(1993年)10.1103/PhysRevett.70.2782]。在第二种生长模式中，在930摄氏度到1000摄氏度之间，岛屿通过在正方形两边的中间形成沟渠来缓解压力，从而演变成十字架。这种形状的出现是因为较低的退火温度对岛收窄所需的原子脱离施加了动力学约束。
Extended annealing in UHV causes the surface region of SrTiO3(001) to become enriched with TiO2, resulting in the formation of epitaxial islands of anatase TiO2(001). The islands are studied using UHV scanning electron microscopy (SEM), which reveals the changes in morphology during growth induced by misfit strain. Starting from a square island, two types of shape transition are observed. In the first, between 1000 and 1030 degrees C, the anatase islands elongate in length and narrow in width. This growth behavior follows the Tersoff-Tromp model [Phys. Rev. Lett. 70, 2782 (1993)10.1103/PhysRevLett.70.2782]. In the second growth mode, between 930 and 1000 degrees C, the islands relieve strain by the formation of trenches in the middle of each side of the square, thereby evolving into crosses. This shape arises because the lower annealing temperature imposes a kinetic constraint on the detachment of atoms necessary for island narrowing.