Skolkovo Institute of Science and Technology, Moscow 121205, Russia.
Phys Chem Chem Phys. 2023 Feb 15;25(7):5501-5509. doi: 10.1039/d2cp04405f.
By employing density functional theory calculations, we explore the initial stage of competitive alloying of co-deposited silver and indium atoms into a silicon surface. In particular, we identify respective adsorption positions and activation barriers governing their diffusion on a dimer-reconstructed silicon surface. Furthermore, we develop a growth model that appropriately describes diffusion mechanisms and silicon morphology with the account of silicon dimerization and the presence of C-type defects. Based on the surface kinetic Monte Carlo simulations, we examine the dynamics of bimetallic adsorption and elaborate on the temperature effects on the submonolayer growth of an Ag-In alloy. A close inspection of adatom migration clearly indicates effective nucleation of Ag and In atoms, followed by the formation of orthogonal atomic chains. We show that the epitaxial bimetallic growth might potentially lead to exotic ordering of adatoms in the form of anisotropic two-dimensional lattices orthogonally oriented single-metal rows. We argue that this scenario becomes favorable provided above room temperature, while our numerical results are shown to be in agreement with the experimental findings.
我们运用密度泛函理论计算方法，研究了共沉积的银和铟原子在硅表面上竞争合金化的初始阶段。具体而言，我们确定了各自的吸附位置和扩散的激活势垒，这些原子在重构的硅表面上扩散。此外，我们开发了一种生长模型，该模型考虑了硅二聚化和 C 型缺陷的存在，适当地描述了扩散机制和硅形态。基于表面动力学蒙特卡罗模拟，我们研究了双金属吸附的动力学，并详细讨论了温度对 Ag-In 合金亚单层生长的影响。对吸附原子迁移的仔细检查清楚地表明，Ag 和 In 原子的有效成核，随后形成了正交原子链。我们表明，外延双金属生长可能导致各向异性二维晶格形式的原子的奇异有序排列，即正交排列的单金属行。我们认为，这种情况在高于室温的情况下是有利的，而我们的数值结果与实验结果一致。
