Atomic layer deposition is a powerful technique for achieving atomic-level control in the deposition of thin films and nanoparticles. The ultrathin noble metal films can be applied in many functional devices, but it is a challenge to obtain such films since the island growth mode generally happens instead of the layer growth mode. In this work, the nucleation and growth of platinum on Si, Al₂O₃, Au, and Ni substrates were studied using (MeCp)PtMe₃ and O₂ plasma as a precursor and a co-reactant, respectively. The evolution of Pt coverage on different surfaces was observed and discussed based on the experimental results by x-ray photoelectron spectra. The chemical adsorption of the precursor and the following processes like metal atom diffusion on substrate surfaces and up-stepping onto the existing metal islands were considered to dominate the growth before continuous films formed. The chemisorption determined the metal coverage on bare substrate surfaces, and the total coverage was influenced by metal atom diffusion and up-stepping behaviors that are determined by surface energy relationships between the deposited metal and substrate surfaces. Pt films were easier to form on Al₂O₃ and Ni surfaces compared with on Si and Au surfaces, respectively. A model was proposed to help to understand the mechanisms in the nucleation and growth processes, involving the chemisorption, diffusion, and up-stepping, which contributed to prepare ultrathin continuous Pt films on different substrates.

中文翻译：

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通过等离子体增强原子层沉积研究 Si、Al2O3、Au 和 Ni 表面的 Pt 生长

原子层沉积是实现薄膜和纳米颗粒沉积中原子级控制的强大技术。超薄贵金属薄膜可以应用于许多功能器件，但由于通常发生岛生长模式而不是层生长模式，因此获得这种薄膜是一个挑战。在这项工作中，使用 (MeCp)PtMe ₃和 O ₂研究了铂在 Si、Al ₂ O ₃、Au 和 Ni 衬底上的成核和生长等离子体分别作为前体和共反应物。基于 X 射线光电子能谱的实验结果，观察和讨论了不同表面上 Pt 覆盖率的演变。前体的化学吸附和随后的过程，如金属原子在基板表面上的扩散和向上步进到现有的金属岛，被认为在形成连续薄膜之前主导了生长。化学吸附决定了裸基板表面上的金属覆盖率，总覆盖率受金属原子扩散和上升行为的影响，这些行为由沉积金属和基板表面之间的表面能关系决定。Pt 薄膜更容易在 Al ₂ O _{3 上形成}和 Ni 表面分别与 Si 和 Au 表面相比。提出了一个模型来帮助理解成核和生长过程中的机制，包括化学吸附、扩散和向上步进，这有助于在不同基板上制备超薄连续 Pt 薄膜。