Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Jiaotong University, Xi'an, 710049, China; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Jiaotong University, Xi'an, 710049, China; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China; School of Manufacturing Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China.
Micron. 2019 Nov;126:102738. doi: 10.1016/j.micron.2019.102738. Epub 2019 Aug 23.
Single-barrel scanning electrochemical cell microscopy (SECCM) can be used to perform electrochemical activity analysis and sample surface imaging simultaneously. Compared to SECM & SICM in imaging, the most significant advantage of SECCM is that it does not need to immerse sample in solution, which avoids the electrochemical reaction between electrolyte and sample surface. In traditional direct current (DC) topographic imaging method of SECCM, when the meniscus droplet is contacted with the sample surface, the presence of the redox current determines the Z-height of a scanning point. However, there are some problems in DC mode. Firstly, the redox (Faraday) current is very small (pA/nA), which is susceptible to interference of ambient environment. Secondly, since the inertia of the droplet, the overall height of the imaged topography depends on the droplet size (probe tip diameter) and scanning speed. Therefore, this paper first proposes a single-barrel SECCM circuit model and verifies this circuit model using the first-order zero-state response in the DC mode. Then, an AC scanning mode is proposed, which monitors the change of AC amplitude to determine the Z-height of the scanning point when the meniscus droplet approaches the surface of the sample. The experiments demonstrate that the AC mode has a powerful ability to overcome interference and provide high-stable topographic imaging.
单管扫描电化学池显微镜（SECCM）可用于同时进行电化学活性分析和样品表面成像。与 SECM 和 SICM 在成像方面相比，SECCM 的最大优势是不需要将样品浸入溶液中，从而避免了电解质和样品表面之间的电化学反应。在 SECCM 的传统直流（DC）形貌成像方法中，当微弯液面与样品表面接触时，氧化还原电流的存在决定了扫描点的 Z 高度。然而，在 DC 模式下存在一些问题。首先，氧化还原（法拉第）电流非常小（pA/nA），容易受到环境干扰。其次，由于液滴的惯性，所成像的形貌的整体高度取决于液滴的大小（探针尖端直径）和扫描速度。因此，本文首先提出了单管 SECCM 电路模型，并使用 DC 模式下的一阶零状态响应对该电路模型进行了验证。然后，提出了一种交流扫描模式，该模式监测交流幅度的变化，以确定微弯液面接近样品表面时扫描点的 Z 高度。实验表明，交流模式具有强大的抗干扰能力，并能提供高稳定的形貌成像。
