Scanning Force Microscope

根据这一提议，需要资金购置一台扫描力显微镜（AFM，原子力显微镜）。该仪器应用于记录材料对比度，特别是软样品，以及溶液中电极表面的研究和局部改性。扫描力显微镜利用显微镜尖端和样品之间的力。尖端位于悬臂的末端，尺寸在微米范围内。力引起悬臂的偏转，其通过从悬臂的背面反射到分裂光电二极管上的激光束来测量。机械致动器将尖端顺序扫描到样品的不同位置。在此过程中，控制变量，例如，偏转通过电子反馈回路保持恒定。尖端位置的所需垂直调整的存储值可以转换为假色图像。当在每个位置存储完整的力-距离曲线时，该方法的机会显著增强，除了偏转和修改的尖端之外，还可以使用其他测量量，从而可以得出样品局部机械，电气和电化学性质的结论。要获得的仪器将用于研究表面的自组装过程或有机分子。这些层对于生物膜的实验模型的产生起着重要作用，利用这些模型，可以在生物有机体外部的明确定义的条件下研究基本过程。此外，电化学可切换功能层应在膜形成过程及其电气和电化学特性方面进行研究。新仪器还将用于了解腐蚀过程中氧化层的形成和电池内界面的演变。该仪器的多功能也将用于表征与层状氧化物材料接触的复杂纳米颗粒的表面，用于催化和能量储存。为此，重要的是在成像过程中切换样品的状态。仪器的尖端不仅应用作测量探针，还应用作纳米尺寸范围内局部表面改性的工具。中空杠杆例如可用于局部输送用于金属结构电沉积的试剂溶液。另一种方法旨在修改尖端以获得用于局部光谱学的纳米尺寸的等离子体光发射器。

With this proposal, funds are requested for the acquisition of a scanning force microscope (AFM, atomic force microscope). The instrument shall be used for recording materials contrasts, especially for soft samples as well as for the study and local modification of electrode surfaces in solution. Scanning force microscopy exploits forces between a microscopic tip and the sample. The tip is located at the end of a cantilever with a size in the micrometer range. The forces cause a deflection of the cantilever which is measured by a laser beam reflected from the backside of the cantilever onto a split photodiode. A mechanical actuator scans the tip sequentially to different locations of the sample. During this process, a control variable, e.g., the deflection, is kept constant by an electronic feedback loop. The stored values of the required vertical adjustment of the tip position can be transformed to a false-color image. The opportunities of the method are significantly enhanced, when a complete force-distance curve is stored at each location, other quantities measured besides deflection and modified tip are used that allow conclusion on local mechanical, electrical and electrochemical properties of the sample.The instrument to be acquired will be used to study self-assembly processes or organic molecules at surface. Such layers play an important role for the generation of experimental models of biological membranes, with which essential processes can be studied under well-defined conditions outside biological organisms. Furthermore, electrochemically switchable functional layers shall be studied with respect to film formation processes and their electrical and electrochemical properties. The new instrument will also be used to understand the formation of oxide layers in corrosion processes and the evolution of interphases within batteries. The versatile capabilities of the instrument will also be employed for the characterization of the surfaces of complex nanoparticles in contact with layered oxide materials for catalysis and energy storage. For this purpose, it is important to switch the state of the sample during the imaging process. The tip of the instrument shall not only be used as measurement probe but also as a tool for local surface modification in the nanometer size regime. Hollow cantilevers can for instance be used for the local delivery of reagent solutions for the electrodeposition of metal structures. Another approach aims for the modification of the tips to obtain nanometer-sized plasmonic light emitters for local spectroscopy.