Strong asymmetric effect of lattice mismatch on epilayer structure in thin-film deposition
Strong asymmetric effect of lattice mismatch on epilayer structure in thin-film deposition
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DOI：
10.1103/physrevb.79.155414
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发表时间：
2009-04-01
影响因子：
3.7
通讯作者：
Yu, Ge-Ping
中科院分区：
文献类型：
--
作者：
Hsiao, Pai-Yi;Tsai, Zhuo-Han;Yu, Ge-Ping
我们通过分子动力学模拟研究了沉积在（001）衬底上的薄膜的异质外延生长，使用六种fcc过渡金属作为我们的建模系统。通过研究薄膜层的径向分布函数，我们证明了晶格失配符号对薄膜层结构的重要性。对于正晶格错配，薄膜有利于伪晶生长，而对于负晶格错配，在前几个单原子层内发生急剧转变，薄膜层转变为紧密排列（111）结构。我们提出了一种方法来量化薄膜中不同平面结构的组成百分比，并证明了拉伸和压缩情况下沉积之间的强烈不对称效应。讨论了温度对非对称性的影响。
We investigate the heteroepitaxial growth of thin film deposited on a (001) substrate via molecular-dynamics simulations, using six fcc transition metals as our modeling systems. By studying the radial distribution function in the film layers, we demonstrate the importance of the sign of lattice mismatch on the layer structure. For positive lattice mismatches, the film favors pseudomorphic growth, whereas for negative mismatches, a sharp transition happens within the first few monolayers of adatoms and the film layers are transformed into the close-packed (111) structure. We propose a way to quantify the compositional percentage of different planar structures in an epilayer and demonstrate the strong asymmetric effect between the tensile and compressive cases of deposition. How temperature affects the asymmetry is also discussed.