Atomic force microscopy (AFM)

The topic of Atomic Force Microscopy (AFM) will be introduced through its fundamental principles and key components, focusing on how a nanoscale tip interacts with sample surfaces to generate detailed topographical maps. We will cover how AFM measures surface forces, the role of different scanning modes, and factors influencing spatial resolution and performance. Finally, we will look at AFM’s applications in materials science and biomedicine, highlighting its strengths in imaging and characterization as well as its limitations in speed and scanning area. Atomic Force Microscopy, or AFM, is a versatile technique for imaging and characterizing surfaces at the nanometre and even atomic scale. AFM scans a sharp probe, or tip, over the sample’s surface. Key components include a cantilever with a nanoscale tip, a laser and photodetector to monitor deflection, a precise scanner—often piezoelectric—and an electronic feedback system. This setup enables highly detailed topographical maps, even down to individual atoms. The sensitivity of AFM stems from how its tip interacts with the sample. As the tip moves over the surface, attractive van der Waals forces at longer distances and repulsive forces at close range cause the cantilever to bend or oscillate. The feedback mechanism maintains controlled force or constant height, while AFM electronics monitor cantilever deflection and adjust scanner position. This allows the tip to follow the surface contours and resolve features