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利用分子动力学模拟方法研究了Cu/Au(001)和Au/Cu(001)异质外延岛的演化行为.研究结果显示:Cu-Au体系的相互外延行为呈现出明显的非对称性.Cu在Au(001)基体表面可以形成完整的外延结构,而Au在Cu(001)基体表面外延将导致失配位错的出现.导致非对称外延生长行为的根本原因是外延岛的应变状态的差异和外延岛自身性质的不同.随着外延岛的长大,Cu外延岛与Au(001)基体的微观失配度由最初的接近宏观失配度的9%左右迅速单调下降,并最终趋于晶格匹配;而Au在Cu(001)基体表面外延的微观失配度则呈现出振荡增加趋势.Cu/Au(001)体系的基体形变主要发生在外延岛的边缘,而Au/Cu(001)体系的基体形变主要发生在外延岛内部所对应的区域.
The evolution behavior of Cu / Au (001) and Au / Cu (001) heteroepitaxial islands was investigated by molecular dynamics simulation. The results show that the mutual epitaxial behavior of Cu-Au system exhibits obvious asymmetry. The complete epitaxial structure can be formed on the surface of Au (001) substrate, and the epitaxial growth of Au on the Cu (001) substrate surface will lead to the misfit dislocations. The fundamental reason for the asymmetric epitaxial growth behavior is the difference in the strain state of the epitaxial islands And the nature of the island itself.With the growth of the island, the micro mismatch between the Cu island and the Au (001) matrix decreases rapidly and monotonically from about 9% Lattice mismatch, but the micro mismatch degree of Au epitaxy on Cu (001) substrate shows a tendency of increasing oscillation.The matrix deformation of Cu / Au (001) system mainly occurs on the edge of epitaxial island, while Au / Cu ) Matrix deformation mainly occurs in the region corresponding to the interior of the epitaxial island.