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利用分子动力学弛豫方法模拟了Au/Cu(001)异质外延生长初期Au异质外延岛的形貌演化,分析了Au外延岛演化过程中的局域应力及与基体结合能随表面岛尺寸的变化.研究结果表明当异质外延岛小于7×7时,外延岛原子分布呈现赝Cu点阵形貌;当外延岛达到8×8后,外延岛内开始出现失配位错,失配位错数量随外延岛尺寸的增加而增加.局域压力分析指出,外延岛上原子之间的近邻环境不同导致了所受应力的差异,而外延岛的形变则是由外延岛原子的应力分布所决定.研究还发现,失配位错的产生导致错位原子与基体原子之间的结合强度减弱,但相对增加了非错位原子与基体原子之间的结合强度.
The morphological evolution of Au heteroepitaxial island during the initial stage of Au / Cu (001) heteroepitaxial growth was simulated by molecular dynamics relaxation method. The local stress and the binding energy with Au matrix during the evolution of Au epitaxial island were analyzed. The results show that when the heteroepitaxial island is smaller than 7 × 7, the atomic distribution of the epitaxial island exhibits pseudo-Cu lattice morphology. When the epitaxial island reaches 8 × 8, the misfit dislocation begins to appear in the epitaxial island, The number of coordination errors increases with the increase of the size of the epitaxial island.The analysis of local pressure shows that the difference of the adjacent stresses leads to the difference of the stresses between the atoms in the epitaxial island and the deformation of the island is caused by the stress of the island atoms Distributions.The study also found that the misfit dislocations lead to the weakening of the bond strength between the dislocated atoms and the matrix atoms but relatively increase the bond strength between the non-dislocated atoms and the matrix atoms.