Scanning probe microscopy (SPM) techniques like atomic force microscopy (AFM) and scanning tunneling microscopy (STM) allow for high-resolution visualization and characterization of materials at the nanoscale. AFM works by scanning a probe with a sharp tip across a sample surface, measuring deflections to create a topography image, while STM uses quantum tunneling of electrons between a tip and conductive surface. These techniques provide sub-nanometer resolution and enable measurement of properties like conductivity, adhesion, and magnetic fields. SPM has advanced understanding of nanoscale phenomena in fields such as electronics, catalysis, and biophysics.

1. Nanoscale Visualization
and Characterization
by Scanning Probe
Microscopy
Name : Ritesh Mahanty
IMH/10033/19
Name :Rupesh Mahanty
IMH/10035/19

2. what is nanoscale visualization and characterization ?
Nanoscale visualization and characterization refer to the techniques used to observe and
analyze structures and phenomena at the nanometer scale, which is the scale of atoms and
molecules. These techniques allow researchers to visualize and measure the properties of
materials and devices at the nanoscale level.
Visualization techniques for nanoscale characterization include various forms of microscopy,
such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic
force microscopy (AFM), and scanning tunneling microscopy (STM). These techniques can
provide high-resolution images and information about the size, shape, and composition of
nanoscale structures.

3. Characterization techniques for nanoscale materials include spectroscopy, which involves using
light or other forms of radiation to analyze the chemical and physical properties of materials.
Examples of spectroscopy techniques used in nanoscience include X-ray photoelectron
spectroscopy (XPS), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR).
Other characterization techniques used in nanoscience include diffraction techniques, such as
X-ray diffraction (XRD) and neutron diffraction, which can be used to determine the crystal
structure of materials at the nanoscale level.
Overall, nanoscale visualization and characterization play a critical role in understanding the
properties and behavior of materials and devices at the nanoscale level, which is essential for
the development of new technologies in fields such as electronics, materials science, and
biotechnology.

4. Nanoscale visualization and characterization technique by
scanning probe microscopy

5. Scanning Probe Microscopy (SPM) is a family of techniques used for nanoscale
visualization and characterization of materials. The most commonly used techniques in SPM
are Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM).
AFM operates by scanning a tiny probe over a sample's surface. The probe is attached to a
cantilever, and its deflection is measured using a laser beam. As the probe scans the surface, it
experiences atomic forces between the probe and the sample, which causes deflections in the
cantilever. These deflections are then converted into an image that represents the sample's
surface topography.

6. STM , on the other hand, operates by scanning a sharp metal tip across the surface of a conductive
material. The tip is brought very close to the surface, and a voltage is applied between the tip and
the sample. This creates a tunneling current that is highly sensitive to the distance between the tip
and the sample.
The STM can achieve sub-atomic resolution, allowing for the visualization of individual atoms on a
surface. It can also be used to measure the electronic properties of materials such as local density
of states and conductance.
Both AFM and STM have been used to study a wide range of materials, including metals,
semiconductors, polymers, and biological materials. They are powerful tools for understanding the
properties of materials at the nanoscale, and their applications range from basic research to
industrial quality control.

7. AFM technique of scanning probe microscopy for nanoscale
visualization and characterization.
Atomic force microscopy (AFM) is a type of scanning probe microscopy that enables high-
resolution imaging and characterization of surfaces at the nanoscale. In AFM, a tiny cantilever
with a sharp tip at its end is used to scan the surface of a sample. As the tip moves across the
surface, it interacts with the surface and the cantilever bends, and this bending is measured by
a laser beam reflected off the cantilever onto a detector. The deflection data is then used to
create a three-dimensional image of the surface topography.
AFM can be used in several different modes, each of which has its own strengths and
limitations. The most common mode is contact mode, where the tip is in constant contact with
the surface as it scans. This mode provides high-resolution images, but can also cause damage
to the surface if too much force is applied.

8. Another mode is tapping mode, where the tip oscillates at a specific frequency and taps the
surface intermittently as it scans. This mode is less likely to damage the surface and can also
provide information about the material properties of the surface, such as stiffness and adhesion.
AFM can also be used to measure other properties of the surface, such as electrical conductivity,
magnetic properties, and chemical composition. This is done by functionalizing the tip with a
specific molecule or coating that interacts with the surface in a specific way. For example, a
conductive tip can be used to measure electrical conductivity.A magnetic tip can be used to
measure magnetic properties.
Overall, AFM is a powerful technique for nanoscale visualization and characterization, and has
applications in many fields, including materials science, biology, and physics. Its ability to provide
high-resolution images and measure a variety of properties make it a valuable tool for studying the
properties of surfaces and materials at the nanoscale.

9. STM technique of scanning probe microscopy for nanoscale visualization
and characterization.
Scanning Tunneling Microscopy (STM) is a powerful technique used in the field of
nanotechnology to visualize and characterize surfaces at the atomic and molecular level. It was
developed in the early 1980s by Gerd Binnig and Heinrich Rohrer, who were awarded the Nobel
Prize in Physics in 1986 for their work on this technique.
The STM technique is based on the principle of quantum tunneling, where a thin conducting tip is
brought very close to a conducting surface, and a voltage is applied between them. If the voltage
is small enough, electrons can tunnel through the vacuum between the tip and the surface,
creating a tunneling current that is sensitive to the distance between the tip and the surface.

10. The STM works by scanning the tip over the surface in a raster pattern while keeping the
tunneling current constant. The tip is mounted on a scanner that can move the tip with sub-
nanometer precision in three dimensions. The tunneling current is monitored by a feedback
circuit, which adjusts the tip height to maintain a constant current as the tip scans over the
surface.
As the tip scans over the surface, it creates a three-dimensional map of the surface topography
based on the tunneling current. The resolution of the STM is typically better than one angstrom
(0.1 nm), which is sufficient to resolve individual atoms and molecules on a surface.
STM is capable of not only imaging but also manipulating surfaces at the atomic level. By
applying a voltage to the tip, the STM can induce chemical reactions on the surface, such as
desorption, adsorption, and surface diffusion. This capability has led to the development of
new methods for fabricating nanoscale structures.

11. Advantages
of nanoscale
visualization
and
characterization
by scanning
probe
microscopy

12. Scanning probe microscopy (SPM) is a powerful set of techniques that allows for imaging and
characterization of materials at the nanoscale. Here are some advantages of nanoscale
visualization and characterization by scanning probe microscopy:
High resolution: SPM offers sub-nanometer resolution, allowing for the observation of features
that are too small to be seen with other techniques such as optical microscopy.
Non-destructive: SPM is a non-destructive imaging technique, which means that it does not
damage the sample being studied. This is particularly useful for studying delicate or fragile
samples.

13. Scanning Probe Microscope

14. Versatility: SPM can be used to image a wide range of materials, including metals,
semiconductors, polymers, and biological samples. It can also be used to characterize various
physical and chemical properties such as conductivity, adhesion, and magnetic properties.
In-situ observation: SPM can be used to observe dynamic processes in real-time. For example, it
can be used to study the growth and assembly of nanoparticles or the movement of individual
molecules.
Quantitative analysis: SPM can be used to obtain quantitative information about surface
properties, such as surface roughness or surface energy. This information can be used to
optimize processes such as material synthesis and surface treatment.
Overall, SPM provides a powerful tool for understanding the properties and behavior of
materials at the nanoscale .

15. Disadvantages
of nanoscale
visualization
and
characterization
by scanning
probe
microscopy.

16. While scanning probe microscopy (SPM) has revolutionized our ability to visualize and manipulate
matter at the nanoscale, there are also some disadvantages associated with this technique. Here
are some of the main ones:
Limited field of view: Scanning probe microscopy can only image a very small area at a
time, typically just a few square nanometers. This means that it is not suitable for imaging large-
scale features or surfaces.
Surface sensitivity: Scanning probe microscopy is very sensitive to the surface of a sample,
which can make it difficult to image samples with rough or uneven surfaces. In addition, it can be
difficult to distinguish between surface features and subsurface features.

17. Slow imaging speed: Scanning probe microscopy is a slow technique, and it can take
several minutes or even hours to acquire a single image. This makes it impractical for
imaging large areas or for studying dynamic processes.
Sample preparation: Preparing samples for scanning probe microscopy can be a time-
consuming and technically challenging process. Samples must be clean, flat, and free of
contaminants, and they must be able to withstand the high vacuum environment required
for imaging.
Instrumentation cost: Scanning probe microscopy requires expensive instrumentation,
and the cost can be prohibitive for many researchers or institutions.
Tip wear and drift: The tips used in scanning probe microscopy can wear down over
time, which can affect the quality of the images obtained. In addition, the tip can drift over
time, which can make it difficult to maintain a consistent imaging position.

18. Comparison of SPM with other nanoscale visualization and
characterization techniques.
Scanning Probe Microscopy (SPM) is a powerful tool for nanoscale visualization and
characterization. Here is a comparison of SPM with some other commonly used nanoscale
visualization and characterization techniques:
Transmission Electron Microscopy (TEM): TEM is an imaging technique that uses electrons to
image the sample. It has a higher spatial resolution than SPM but requires a high vacuum
environment and thin samples. SPM, on the other hand, can be used to image a wide range of
samples and does not require a vacuum environment.
Atomic Force Microscopy (AFM): AFM is a type of SPM that uses a sharp probe to scan the
surface of a sample. It can be used in a wide range of environments, including air and liquids,
and can provide information on surface topography, mechanical properties, and electrical
properties.

19. Scanning Electron Microscopy (SEM): SEM is an imaging technique that uses electrons to
image the sample. It has a lower spatial resolution than TEM but can be used to image a wider
range of samples and can provide information on surface morphology and elemental composition.
X-ray Diffraction (XRD): XRD is a technique that is used to determine the crystal structure of a
material. It is not a direct imaging technique like SPM or TEM, but it can provide important
information about the structure of the sample.
Raman Spectroscopy: Raman spectroscopy is a technique that is used to study the vibrational
modes of a material. It can provide information on the chemical composition and bonding of the
sample but has a lower spatial resolution than SPM.
In summary, SPM is a versatile technique that can provide information on surface topography,
mechanical properties, and electrical properties of a wide range of samples. While other
techniques like TEM and SEM have higher spatial resolution, they are limited in the types of
samples that can be imaged and the environments in which they can be used

20. Conclusion:--
Scanning probe microscopy (SPM) is a powerful tool for visualizing and characterizing materials
at the nanoscale. SPM techniques, such as atomic force microscopy (AFM) and scanning
tunneling microscopy (STM), allow for the imaging of surfaces with sub-nanometer resolution
and the measurement of various physical properties such as conductivity, mechanical
properties, and magnetic fields.
The development of SPM techniques has greatly expanded our understanding of the physical,
chemical, and biological properties of materials at the nanoscale. SPM has enabled researchers
to study surface morphology, topography, and the arrangement of atoms and molecules with
high precision. This has led to new discoveries in fields such as nanoelectronics, catalysis, and
biophysics.
Despite its advantages, SPM has some limitations, such as the difficulty of imaging certain
materials and the risk of sample damage. Additionally, SPM techniques are relatively slow and
require specialized equipment and expertise.
Overall, SPM has revolutionized the way we study materials at the nanoscale and has opened up
new avenues for scientific research and technological innovation.

21. References :
• Research Gate
• News medical (https://www.news-medical.net/life-
sciences/What-is-Scanning-Probe-Microscopy.aspx)
• Science Direct
(https://www.sciencedirect.com/topics/engineering/scanni
ng-probe-microscope)
• Oxford Instruments (https://afm.oxinst.com/outreach/spm-
scanning-probe-microscopy)