Study of structural morphology of electrodeposited Ni thin film on Au(111) substrate.

我们的中心目标是了解多晶电沉积金属薄膜的微观结构和表面形貌（晶界，生长速度）。电沉积金属薄膜具有多种应用，其中微观结构和表面形貌对其性能起着关键作用，从装饰和耐腐蚀涂层到超大规模集成电路中的连接器。电阻和耐化学性也可以通过微结构来控制。特别是，电沉积镍以其广泛的用途和独特的特性在电沉积多晶金属薄膜中具有特殊的吸引力。镍涂层被广泛用于提高耐蚀性和耐磨性，其力学性能使其特别适用于电沉积制造的微机电系统（MEMS）。Ni也引起了人们的极大兴趣，因为尽管Ni与Cu具有相同的fcc晶体结构，但它的研究引入了新的特征。在室温下，Ni的原子迁移率明显低于Cu，这是通过扩散系数进行严格评估的，这抑制了晶粒粗化并导致更明显的柱状织构，并且与Cu不同，Ni沉积通常发生在析氢重要的电位下，这可以通过表面吸附强烈地改变织构。然而，尽管它们具有重要意义，是什么决定了多晶电沉积金属薄膜的微观结构和表面形貌的问题在很大程度上仍然没有解决。生长驱动晶粒粗化或缺陷处新晶形核的详细机制仍需注意了解。我们的项目将通过利用两项主要技术进步，高速原子力显微镜（HS-AFM）和Xe等离子体聚焦离子束（等离子体FIB）铣削来克服这一实验瓶颈。我们将研究镍电沉积薄膜的微观结构与表面形貌的关系。原位HS-AFM将在生长过程中提供高分辨率的表面形貌，而等离子体FIB铣削将用于切割所得薄膜，通过电子背散射衍射（EBSD）表征不同深度的晶粒结构。结合HS-AFM和EBSD数据将使我们能够将表面结构演变与同一区域薄膜沉积后的微观结构联系起来，并将使用非常快速和方便的测量技术来实现这一目标。我们相关联的体和表面数据将为定量研究提供电沉积的关键方面。例如，晶体取向和生长速率之间的关系从未在实际电沉积条件下通过实验建立，尽管它是理解多晶生长的基础。通过比较连续的HS-AFM图像，我们可以测量局部生长速率，并将其与基粒的取向相关联。通过改变电解质组成，我们将能够观察到不同的吸附剂对取向依赖性生长速率的影响，从而为添加剂控制薄膜形态和织构的作用提供有益的见解。该项目属于EPSRC物理科学研究领域。

Our central aim is to understand the microstructure and surface morphology (grain boundaries, growth rate) of polycrystalline electrodeposited metal films. Electrodeposited metal films have multiple applications where microstructure and surface morphology play key role to their performance, from ornamental and corrosion-resistant coatings to connectors in ultra-large-scale integrated circuits. Electrical and chemical resistance can also be controlled by microstructures. Specially, electrodeposited Ni has special attraction in electrodeposited polycrystalline metal thin films because of its many applications and unique features. Ni coatings are widely used to improve corrosion and wear resistance, and its mechanical properties make Ni especially useful for micro-electromechanical systems (MEMS) fabricated by electrodeposition. Ni is also of great interest because although Ni shares the fcc crystal structure with Cu, its study introduces new features. Atomic mobilities are significantly lower for Ni than Cu at room temperature which was critically assessed by diffusion coefficient, which suppresses grain coarsening and leads to a more pronounced columnar texture, and unlike Cu, Ni deposition usually takes place at potentials where hydrogen evolution is important, which can strongly modify the texture via surface adsorption. However, despite their significance, the problem of what determines the microstructure and surface morphology of a polycrystalline electrodeposited metal film is still largely unsolved. The detailed mechanism for growth driven grain coarsening or nucleation of new grains at defect still need attention to understand. Our project will overcome this experimental bottleneck by exploiting two major technical advances, high speed atomic force microscopy (HS-AFM) and Xe plasma focussed ion beam (plasma FIB) milling. We shall investigate the relation between microstructure and surface morphology of Ni electrodeposited thin film. In-situ HS-AFM will provide high-resolution surface topography during growth, while plasma FIB milling will be used to section the resulting film to characterize the grain structure at different depths by electron backscatter diffraction (EBSD). Combining HS-AFM and EBSD data will enable us to correlate surface structure evolution with the post-deposition microstructure of the same area of film and to will do so using exceptionally rapid and convenient measurement techniques. Our linked bulk and surface data will provide key aspects of electrodeposition to quantitative study. For example, the relation between crystallographic alignment and growth rate has never been established experimentally under realistic electrodeposition conditions, despite it being fundamental to understanding polycrystalline growth. By comparing successive HS-AFM images we can measure local growth rates and correlate them with the orientations of the basal grains. By changing the electrolyte composition, we shall be able to observe the effect of different adsorbates on orientation-dependent growth rate, providing beneficial insight into the role of additives to control film morphology and texture. This project falls within the EPSRC Physical science research area.