The atomic force microscope (AFM) is one kind of scanning probe microscopes (SPM). SPMs are designed to measure local properties, such as height, friction, magnetism, with a probe . To acquire an image, the SPM raster-scans the probe over a small area of the sample, measuring the local property simultaneously.
What type of information can one extract by an AFM analysis?
From AFM you may extract a wide range of informations: 3D topography , mechanical properties (Harness elastic modulus, storage and loss modulii), adhesion, chemical informations by functionalizing your probe tip, electrical conductivity, thermal conductivity, electrostatic forces, magnetic forces....
What can AFM be used for?
The AFM can be used to image the topography of soft biological materials in their native environments . It can also be used to probe the mechanical properties of cells and extracellular matrices, including their intrinsic elastic modulus and receptor-ligand interactions.
How does AFM measure force?
An AFM uses a cantilever with a very sharp tip to scan over a sample surface . As the tip approaches the surface, the close-range, attractive force between the surface and the tip cause the cantilever to deflect towards the surface. ... A laser beam is used to detect cantilever deflections towards or away from the surface.
What can be measured by AFM?
An AFM is a mechanical imaging instrument that measures the three dimensional topography as well as physical properties of a surface with a sharpened probe , (see Figure 1-1). The sharpened probe is positioned close enough to the surface such that it can interact with the force fields associated with the surface.
What is the principle of AFM?
The underlying principle of AFM is that this nanoscale tip is attached to a small cantilever which forms a spring . As the tip contacts the surface, the cantilever bends, and the bending is detected using a laser diode and a split photodetector. This bending is indicative of the tip-sample interaction force.
Which mode of AFM is mostly used for solid surface?
Different modes of AFM, including contact mode , noncontact mode, and tapping mode [25]. The contact mode in which the tip of the cantilever scans the sample in close contact with the surface is the most commonly used method for surface force measurements.
What kind of surfaces Cannot be scanned using an AFM?
Additionall, a non planar sample is difficult to scan with an AFM, though there has been some isolated reports of imaging non planar surfaces with change in mounting. Very sticky and adhesives alos cannot be scanned with an AFM as it makes the tip stick to the sample surface, which is known as tip crash.
Which of the following device is used in AFM?
The AFM consists of a cantilever with a sharp tip (probe) at its end that is used to scan the specimen surface. The cantilever is typically silicon or silicon nitride with a tip radius of curvature on the order of nanometers.
Which of the following are the parts of AFM?
- Dimensions and Magnification. ...
- Piezoelectric Ceramic Transducer. ...
- Force Sensors. ...
- Feedback Control. ...
- Atomic Force Microscope. ...
- AFM Theory. ...
- AFM Instrumentation.
What are the limitations of AFM?
The scanning speed of an AFM is also a limitation. Traditionally, an AFM cannot scan images as fast as a SEM, requiring several minutes for a typical scan, while a SEM is capable of scanning at near real-time, although at relatively low quality.
How does an AFM work in tapping mode?
In tapping mode afm, the sharp probe tip is not scanned across the sample surface while in constant contact . Instead, the cantilever is vibrated near its resonance frequency causing the tip to oscillate up and down. This means the probe only comes into close contact with the surface intermittently; hence the title.
What are the advantages of AFM over SEM?
On atomically smooth surfaces, AFM is capable of producing a three-dimensional topography using just a single scan . AFM also provides a greater level of detail for these surfaces, as SEM is not as efficient in resolving the subtle changes on a highly smooth surface.
Is AFM destructive?
Since then it has developed into a powerful measurement tool for surface analysis. AFM allows accurate and non-destructive measurements of the topographical, electrical, magnetic, chemical, optical, mechanical, etc. properties of a sample surface with very high resolution [2] in air, liquids or ultrahigh vacuum.
What is the basic principle based on which AFM images are obtained?
The AFM principle is based on the cantilever/tip assembly that interacts with the sample ; this assembly is also commonly referred to as the probe. The AFM probe interacts with the substrate through a raster scanning motion.
What is the limiting factor with respect to AFM resolution?
The main limiting factor of the imaging rate of AFM is the response speed of the moving components of the atomic force microscope, i.e., the probe and the scanner .
