AFM is one of the foremost tools for imaging, measuring, and manipulating matter at the Nanoscale. It Is a very high-resolution, type of Scanning Probe Microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit.

1. ATOMIC FORCE MICROSCOPY
S. M GHARIB NAWAZ

2. ATOMIC FORCE MICROSCOPY ( AFM)
One of the foremost tools for imaging, measuring, and manipulating matter
at the Nano scale.
Is a very high-resolution,
 type of Scanning Probe Microscopy (SPM),
with demonstrated resolution on the order of fractions of a nanometer, more
than 1000 times better than the optical diffraction limit.

3. ATOMIC FORCE MICROSCOPY ( AFM)
The information is gathered by "feeling" or "touching" the surface with a
mechanical probe.
Offers image resolution down to the atomic scale

4. HOW DOES AFM WORK?
Force depends on nature of sample, probe geo., spring constant of
probe, distance between probe & sample, and any contamination on
surface.
An atomically sharp tip is scanned over surface with feedback
mechanisms that enable the piezo-electric scanners to maintain the tip at
a constant force (to obtain height info) or height (to obtain force info)
above the sample surface.
Tip is brought close enough to surface to detect repulsive force between
atoms in tip and sample.

5. HOW DOES AFM WORK?
Probe tip is mounted on cantilever. Interatomic forces will induce
bending and can be detected by laser beam. Tips typically made of Si3N4
or Si .
Surface topography of sample is tracked by monitoring deflection of the
cantilever.
Optical detection system – diode laser is focused onto the back of a
reflective cantilever. As tip scans surface, moving up & down with the
contour, laser beam is deflected off into a dual element photodiode.
Measures difference in light intensities between upper & lower photo
detectors & converts to voltage.

6. HOW DOES AFM WORK?

8. DATAANALYSIS:

9. HOW IS FORCE MEASURED?

11. DIFFERENT TYPES OF TIPS:

12. DIFFERENT IMAGING MODES:
1. Static mode (contact mode),
1. Dynamic mode (non-contact mode and tapping mode)

13. CONTACT MODE:
ADVANTAGES:
high resolution,
fast scanning,
good for rough samples.
DISADVANTAGE:
May damage the samples and tip.

14. NON-CONTACT MODE:
ADVANTAGE:
very low force exerted on the sample.
tip will be in its original form as its
too expensive.
DISADVANTAGES:
lower resolution,
contaminant layer on surface can interfere
with oscillation; usually need ultra high
vacuum (UHV) to have best imaging,

15. INTERMITTENT CONTACT (TAPPING)
MODE:
High resolution of samples that are easily damaged.
Good for biological samples.
Used for imaging in air.

16. APPLICATIONS:
Study Unfolding Of Proteins,
Imagining Of Biomolecules,
Force Measurements In Real Solvent Environments,
Antibody-Antigen Binding Studies,
Ligand-Receptor Binding Studies,
Binding Forces Of Complimentary DNA Strands,
Study Surface Frictional Forces,
Ion Channel Localization,
Imagining Of Nanoparticles.

18. THANK YOU
FEEL FREE TO ASK QUESTIONS.