Institute of Physics of Academy of Sciences of the Czech Republic, v.v.i., Na Slovance 2, CZ-18221 Prague 8, Czech Republic.
J Phys Condens Matter. 2012 Apr 4;24(13):135003. doi: 10.1088/0953-8984/24/13/135003. Epub 2012 Feb 28.
Recent experiments on epitaxial growth of metals on graphene have shown a strong dependence of island densities on coverage. These investigations cannot be explained by the standard mean-field nucleation theories. To understand them, we extend to higher coverage the former theory of rate equations developed for the initial state of nucleation, in a system where adsorbate interaction is included. We account for that, in the case of high coverage, the repulsive interaction influences both the attachment of monomers to clusters and the mobility of atoms. In our work we analyze the modification of the dependence of the island density on coverage, temperature and F/D ratio. In some regimes our theory results in the experimentally observed substantial growth of island density with coverage for a high deposited amount and a weak dependence on deposition rate F. We also find out the local maxima in temperature dependence of island density, as a consequence of long-range repulsive interactions.
最近关于金属在石墨烯上外延生长的实验表明，岛密度对覆盖率有很强的依赖性。这些研究不能用标准的平均场成核理论来解释。为了理解它们，我们将以前为成核初始状态开发的速率方程理论扩展到更高的覆盖率，在这个系统中包括了吸附物相互作用。在高覆盖率的情况下，我们考虑到排斥相互作用不仅影响单体与团簇的附着，也影响原子的迁移率。在我们的工作中，我们分析了岛密度对覆盖率、温度和 F/D 比的依赖性的修正。在某些情况下，我们的理论导致了实验观察到的随着沉积量的增加而岛密度显著增加，以及对沉积速率 F 的弱依赖性。我们还发现了由于长程排斥相互作用导致的岛密度温度依赖性的局部最大值。
