Atomic Force Microscopy

1、Introduction

Atomic Force Microscopy (AFM) provides a wide range of solutions for analyzing and characterizing materials at the nanoscale. By using AFM, you can gain detailed insights into the physical, chemical, and mechanical properties of your sample, making it a powerful tool for research and development in materials science, biology, nanotechnology, and more.

2、Advantages

High spatial resolution (atomic scale), wide range of materials, minimal sample preparation, non-destructive testing, 3D surface imagingfor nanoscale imaging and material characterization, offering high resolution and versatility.

3、Principle

The AFM operates by measuring the forces between the tip and the sample surface. These forces can include van der Waals forces, electrostatic forces, magnetic forces, and mechanical contact forces. The working principle can be summarized as follows:

1. Tip-Sample Interaction: The sharp tip is brought very close to the sample surface. As the tip scans the surface, it experiences forces that cause the cantilever to deflect.
2. Force Detection: The deflection of the cantilever is detected by the laser-photodetector system. The amount of deflection corresponds to the interaction forces between the tip and the surface.
3. Feedback Mechanism: A feedback loop maintains a constant force (or deflection) by adjusting the height of the tip or sample. This ensures that the tip does not damage the surface and provides accurate measurements.
4. Image Generation: The vertical movement of the tip (z-direction) is recorded as the tip scans across the surface (x and y directions). This data is used to construct a 3D image of the surface topography.

The scope of AFM is vast, spanning from fundamental research to industrial applications. Its ability to provide high-resolution imaging and analyze a wide range of material properties makes it an essential tool in fields like nanotechnology, materials science, biology, and beyond. With ongoing advancements, AFM is poised to play an even greater role in future scientific and technological developments.

Applicable Material Types:

thin films, powders, liquids

Industries and Applications:

Materials Science: surface properties of materials, roughness, texture, and mechanical properties. Nanotechnology: create nanoscale patterns and structures. Biology and Life Sciences: study the morphology and mechanical properties of cells, proteins, and DNA. Surface Chemistry: analyze surface interactions and chemical properties. Semiconductor Industry: quality control and assessing surface defects.

1、How does AFM work?

AFM uses a sharp tip mounted on a flexible cantilever to scan the surface of a sample. As the tip interacts with the surface, the cantilever deflects due to forces like van der Waals, electrostatic, or mechanical contact forces. A laser beam reflects off the cantilever, and a photodetector records the deflection, which is used to generate a 3D image of the surface.

2. What are the main modes of AFM operation?

AFM operates in three primary modes: • Contact Mode: The tip is in continuous contact with the surface, measuring repulsive forces. • Tapping Mode: The cantilever oscillates, and the tip intermittently contacts the surface, reducing damage to soft samples. • Non-Contact Mode: The tip does not touch the surface but measures attractive forces, ideal for fragile or ultra-soft samples.

3. What types of samples can AFM analyze?

AFM can analyze a wide range of samples, including: • Hard materials (metals, ceramics, semiconductors). • Soft materials (polymers, hydrogels, biological samples like cells and proteins). • **Nanomaterials **(nanoparticles, nanotubes, 2D materials like graphene). • Thin films and coatings.

4. What properties can AFM measure?

AFM can measure: • Surface topography: 3D imaging of surface features. • Mechanical properties: Elasticity, hardness, adhesion, and friction. • Electrical properties: Conductivity, surface potential, and charge distribution. • Magnetic properties: Magnetic domain structure. • Thermal properties: Thermal conductivity and expansion.

5. What is the resolution of AFM?

AFM can achieve atomic-scale resolution, with lateral resolution typically in the range of 1–10 nm and vertical resolution as high as 0.1 nm.