Aarts Mark, Reiser Alain, Spolenak Ralph, Alarcon-Llado Esther
Center for Nanophotonics, AMOLF Science Park 109 Amsterdam Netherlands
Laboratory for Nanometallurgy, Department of Materials, ETH Zürich Vladimir-Prelog-Weg 1-5/10 Zürich Switzerland.
Nanoscale Adv. 2022 Jan 13;4(4):1182-1190. doi: 10.1039/d1na00779c. eCollection 2022 Feb 15.
Regulating the state of the solid-liquid interface by means of electric fields is a powerful tool to control electrochemistry. In scanning probe systems, this can be confined closely to a scanning (nano)electrode by means of fast potential pulses, providing a way to probe the interface and control electrochemical reactions locally, as has been demonstrated in nanoscale electrochemical etching. For this purpose, it is important to know the spatial extent of the interaction between pulses applied to the tip, and the substrate. In this paper we use a framework of diffuse layer charging to describe the localization of electrical double layer charging in response to a potential pulse at the probe. Our findings are in good agreement with literature values obtained in electrochemical etching. We show that the pulse can be much more localized by limiting the diffusivity of the ions present in solution, by confined electrodeposition of cobalt in a dimethyl sulfoxide solution, using an electrochemical scanning tunnelling microscope. Finally, we demonstrate the deposition of cobalt nanostructures (<100 nm) using this method. The presented framework therefore provides a general route for predicting and controlling the time-dependent region of interaction between an electrochemical scanning probe and the surface.
通过电场调节固液界面的状态是控制电化学的有力工具。在扫描探针系统中，借助快速电位脉冲可将其紧密限制在扫描（纳米）电极上，这为探测界面和局部控制电化学反应提供了一种方法，正如在纳米级电化学蚀刻中所展示的那样。为此，了解施加在尖端和基底上的脉冲之间相互作用的空间范围很重要。在本文中，我们使用扩散层充电框架来描述响应探针处电位脉冲时双电层充电的局部化。我们的发现与电化学蚀刻中获得的文献值高度一致。我们表明，通过限制溶液中离子的扩散率，使用电化学扫描隧道显微镜在二甲基亚砜溶液中进行钴的受限电沉积，脉冲可以更加局部化。最后，我们展示了使用这种方法沉积钴纳米结构（<100 nm）。因此，所提出的框架为预测和控制电化学扫描探针与表面之间随时间变化的相互作用区域提供了一条通用途径。
