Graphene
As one of the most durable, flexible and conductive 2D materials, Graphene continues to be studied and applied across multiple areas of research and industries. With applications in the energy sector, biomedical advances, electronics, and more, graphene remains a critical focus of research for both theoretical and applied scientists.
Nanonics Multiprobe SPM Systems enable thermal, electrical, and optical transport studies on graphene and other 2D materials. Photoconductivity, AFM, Raman and TERS, as well as SNOM/NSOM measurements, are all available in a variety of environments within the same platform.
Methods
AFM Raman
Integrate AFM topography with Raman spectroscopy in one overlaid map.
AFM image of graphene flake
Raman spectra map of graphene flake
The image on the left is a 10um x 10um AFM height image of a graphene flake showing 2 distinct areas.
The graph on the right depicts Raman spectra collected from the different areas, clearly differentiating the region of the single layer (red spectrum) and the double layer (blue spectrum.)
AFM-Raman map of 2676cm-1 single layer band
AFM-Raman map of the 2700cm-1 double layer band
Raman intensity has been overlaid on top of the AFM 3D topography, where red shows the highest Raman intensity and green shows the lowest Raman intensity [blue coloring corresponds to region without any graphene].
On the left is the AFM-Raman map of the 2676cm-1 single layer band, showing highest distribution of the single layer in the triangular red zone in the top half of the image.
On the right is the AFM-Raman map of the 2700cm-1 double layer band, showing the strongest signal in the top trapezoidal and bottom rectangular orange regions.
Note that the single and double layer band regions are located in different areas of the surface and are easily identified using the Raman maps.
TERS
Identify enhanced band of Graphene with TERS difference mapping.
AFM image of Graphene
Raman/TERS/Difference Graph - point (a)
Raman/TERS/Difference Graph - point (b)
The image on the left is an AFM image of graphene.
In the two corresponding graphs, both far-field Raman (black), TERS (red), and difference (green) spectra have been collected at two different spots on the surface.
Spectra in the center graph were collected at point (a) revealing a single layer of graphene.
Spectra in the graph on the right, collected at point (b), reveal a double layer of graphene.
This kind of difference mapping helps to identify the enhanced band only.
AFM Thermal Conductivity
Study in-situ AFM and thermal conductivity measurements.
AFM (left) and Overlaid AFM/Thermal imaging (right) of graphene flakes
These images demonstrate in-situ AFM and thermal conductivity measurements
AFM Kelvin Probe
Study in-situ AFM and Kelvin probe measurements.
AFM (left) and KPM (right) images of graphene transistor with opposite voltage bias
These images demonstrate in-situ AFM and Kelvin probe measurements
Photoconductivity
Obtain photocurrent images as a function of voltage without far-field background.
Photoconductive image of a graphene transistor
Photoconductive images
Diagram
Photocurrent images of a graphene transistor as a function of voltage without far-field background, using nanometric confinement of illumination in X Y and Z with apertured NSOM
Reference: Super-resolution Imaging of Photocurrent Induced in Graphene Transistor by Near-field Optical Excitation
Mueller, T., Xia, F., Freitag, M., Tsang, J., & Avouris, P.
6. Conductive AFM
AFM image of graphene
Raman spectra map of graphene
Current graph of graphene
Multiprobe conductive AFM characterization with on-line monitoring of current and the 2D Raman scattering band of graphene.
Publications
| Local hole doping concentration modulation on graphene probed by tip-enhanced Raman spectroscopy |
| Iwasaki, T., Zelai, T., Ye, S., Tsuchiya, Y., Chong, H. M., & Mizuta, H |
| Carbon 111 (2017): 67-73. |
| Quantifying Defect Densities in Monolayer Graphene Using Near-field Coherence Measurements. |
| Naraghi, R. R., Cançado, L. G., Salazar-Bloise, F., & Dogariu, A. |
| Frontiers in Optics, pp. FF5B-3. Optical Society of America, 2016. |
| Sn–and SnO 2–graphene flexible foams suitable as binder-free anodes for lithium ion batteries. |
| Botas, Cristina, Daniel Carriazo, Gurpreet Singh, and Teófilo Rojo. |
| Journal of Materials Chemistry A 3, no. 25 (2015): 13402-13410. |
| Enhanced graphene photodetector with fractal metasurface |
| Fang, Jieran, Di Wang, Clayton T. DeVault, Ting-Fung Chung, Yong P. Chen, Alexandra Boltasseva, Vladimir M. Shalaev, and Alexander V. Kildishev. |
| Nano letters 17, no. 1 (2016): 57-62. |
