Different Optical, AFM and Spectroscopy Techniques Provide Unique Opportunities for Investigation of Graphene by NT-MDT

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.

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.

Electrostatic Force Microscopy

Force Modulation Microscopy

Lateral Force Microscopy

Scanning Kelvin Probe Microscopy

AFM Topography. Scan Size: 30 x 30 µm

Confocal Rayleigh Microscopy (473 nm laser)

Raman Map, Mass Center of 2D (G') Band

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.

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.

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.

Source: NT-MDT Co.

For more information on this source please visit NT-MDT Co.

Date Added: Jun 12, 2010 | Updated: Jun 11, 2013
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