ATOMIC FORCE MICROSCOPY

1. ATOMIC FORCE
MICROSCOPY

3. Bulk Material
There is plenty of room at bottom
Micro world 10-6
Physical
properties
remain same
Nano world 10-9
properties totally
changed
KEY PRINCIPLES

4. The AFM, also known as the atomic
force microscope (AFM) is a sort
scanner probe. Its principal functions
include measuring characteristics like
height, magnetism and friction on
nanometer fraction.
To investigate non-conductive
materials like protein.
Atomic Force
Microscopy(AFM)

5.  STM was invented in 1981 which gives the image of matter at Nano
scale level.
 But in STM the sample must be conducting and can work only in
vacuum.
 So to counter these problems of STM, Gerd Binning invented AFM in
1982 & got Nobel prize for his great invention.
 It can make images and manipulation of matter at Nano scale.
 It is also called scanning force microscopy,
 In simple words we can also say that AFM is the improve version of
STM.
Need for AFM

6. PARTS
The main component of AFM is
Cantilever a metal sheet having a
sharp tip at the end.
1. Cantilever
2. Tip
A very fine tip of size of order of
nanometer is composed of Silicon(Si)
And is attached at the end of
cantilever, Hardly combined of 7 to 8
atoms.

7. The sample under
investigation is placed on
platform
4. Platform
5. Piezoelectric tube
The platform containing sample
is mounted on the piezoelectric
tube Which can move sample
in XYZ direction to scanning for
3D view

8. To detect the deflection
in cantilever
To detect the deflection
Between the tip atoms
and sample atoms
6. LASER
It converts laser light/
energy into electrical
energy and then these
electric current signals
detected by computer
it will analyze the
current and displayed
them on screen
7. Photoconductor

10. Principle
AFM works on the principle that a fine sharp tip of the order of nanometer attached to
cantilever when brought into close to a sample surface The Vander walls forces between
the sample produces are deflection of cantilever according to the hooks law the reflection
is measured by laser spot reflected from the top of cantilever into photo detector.
1.Contact mode e.g. hard metals
2.Non contact mode e.g for light surfaces
like biological samples
The most preferable working model is non
contact mode As in contact mode the are
more number of chances of damaging the
Cantilever tip.
Modes of working

11. Advantages
3D image with high resolution
No need of vaccume like Electron microscope
No need of illumination or focusing
Non conducting sample use
Disadvantages
More scan time
More chances of sample distortion