Atomic force microscopy (AFM), a member of the scanning probe microscopy (SPM) family, holds a unique position as a nano-characterization instrument in the fields of physics, chemistry, and biology. Its ability to provide atomic resolution and operate in various environments including, vacuum, air, or liquids, has contributed to its widespread adoption. While it has been capable of high spatial resolution since its invention, the temporal resolution has lagged behind other imaging techniques. The desire to capture bio-molecular dynamics has triggered innovation in high-speed AFM (HS-AFM). The research goals within HS-AFM have spurred technical advances aimed at improving the functionality of various components of AFM. Among these components, the controller has been the central focus of this thesis. The work presented in this thesis became possible thanks to the development of an open-source, modular, research-grade AFM controller.
We present the developed open-source controller, which serves as a versatile and high-performance instrument for research-grade SPM applications. This controller has been successfully utilized in various SPMs, facilitating the realization of numerous research projects, including HS-AFM, correlative microscopy techniques, advanced control schemes, and novel modalities. The presented results highlight its expandable functionalities and its capacity for seamless adaptation to a wide range of SPM systems and imaging techniques.
Additionally, we present a modular, standalone, custom-built HS-AFM system in an open-source fashion. The system's performance is demonstrated by capturing the assembly of blunt-end short arm DNA three point stars at a rate of 10 frames per second. By sharing this platform as an open-source instrument, our aim is to provide a canvas for instrumentation developers to rapidly test and implement their ideas. With a growing hardware repository, developers can integrate individual components into their systems and contribute to the community with their own innovations.
Finally, we introduce a new off-resonance tapping (ORT) AFM feedback-control method, and provide a detailed analysis of the limitations of existing conventional ORT techniques. The proposed method leads to a significant improvement in topography tracking, enabling higher scan rates. We also demonstrate that better tracking at high speeds enhances the accuracy of mechanical property mapping.