.jpg)
Topics Covered
Introduction
Unique Opportunities in
Graphene Investigation
Graphene Studied by Various Optical,
AFM and Spectroscopy Techniques
Further Insight into
Graphene and Graphite Structure
High-Resolution Imaging of Single-Layer
Graphene
Atomic-Resolution
Lattice Images of Graphite
The Equipment
Introduction
Graphene - one layer of carbon atoms arranged in a hexagonal lattice - is the
newest member in the family of carbon allotropes. The interest in graphene is
continuously rising among science communities. Applied physicists, new material
designers, and nanotechnology engineers are attracted by its unique properties
such as electrical and thermal conductivity.
Unique Opportunities in Graphene Investigation
Combination of Atomic Force Microscopy (AFM), Raman / Fluorescence / Rayleigh
microscopy and Scanning Near-Field Optical Microscopy (SNOM) provides unique
opportunities for Graphene investigation. Different AFM techniques allow one to
study mechanical, electrical, magnetic and even elastic properties of Graphene
flakes. Studies of local work function, conductivity, capacitance, piezoresponse
and many other surface properties are also available.
At the same time, Raman microscopy (available simultaneously with AFM)
provides information about flake thickness, structural uniformity, presence of
impurities and defects etc. Additionally, Rayleigh imaging and SNOM measure
local optical properties of the sample providing further information about flake
structure. Importantly, most of the measurements can be performed under
environmental control: at variable humidity and temperature, in controlled
atmosphere, in liquid and even (in some configurations) in electrochemical
environment and at the external magnetic field.
.jpg)
.jpg)
White light image of the graphene flake with AFM tip and Raman
laser
Graphene Studied by Various Optical, AFM and Spectroscopy Techniques
The images below illustrates the use of various optical, AFM and spectroscopy
techniques to investigate grapnehe on Si/SiO2 substrates. Image courtesy
of E.Kuznetsov, S.Timofeev, and P. Dorozhkin, NT-MDT Co.
.jpg)
Electrostatic Force Microscopy |
.jpg)
Force Modulation Microscopy |
.jpg)
Lateral Force Microscopy |
.jpg)
Scanning Kelvin Probe Microscopy |
.jpg)
AFM Topography. Scan Size: 30 x 30 µm |
.jpg)
Confocal Rayleigh Microscopy (473 nm laser) |
.jpg)
Raman Map, Mass Center of 2D (G') Band |
.jpg)
Raman Map, G-band Intensity |
Further Insight into Graphene and Graphite Structure
Further Insight into Graphene and Graphite Structure Can Be Obtained with
Other Very High Resolution SPM Techniques.
High-Resolution Imaging of Single-Layer Graphene
The high-resolution image was taken by AFM and shows an assembly of
single-layer, functionalized Graphene sheets on a surface. Some of the sheets
are many square micrometers large. The thickness of each sheet is less than 1
nm.
.jpg)
Image courtesy: Dr. Hannes Schniepp (The College of William
& Mary, USA)
Atomic-Resolution Lattice Images of Graphite
The picture shows a graphite (HOPG) sample that was imaged by scanning
tunneling microscopy (STM). The scan range of the entire image is less than 7
nm. Excellent atomic resolution is achieved.
.jpg)
Image courtesy: Dr. Hannes Schniepp (The College of William
& Mary, USA)
The Equipment
NTEGRA
Spectra provides the opportunity to carry out all the measurements by the
same instrument, on the same sample during the same experiment. It is possible
to obtain AFM / Raman / Fluorescence / Rayleigh / maps exactly from the same
area during one sample scan. All AFM and spectral data analysis are performed
with the same software.
.jpg)
Source: NT-MDT Co.
For more information on this source please visit NT-MDT
Co.