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Alfa Chemistry provides testing services to analyze graphene layers and thickness. The number of layers is directly related to the quality of graphene products and have a greater impact on its electrical and thermal conductivity properties. We use various effective methods to test and analyze unprocessed graphene and devices made from it. Alfa Chemistry's analysis and testing capabilities can meet your personalized data analysis needs and provide comprehensive data analysis results.
Atomic Force Microscopy (AFM) is the most direct and effective tool for graphene layer characterization.
Figure 1. AFM image of CVD-grown graphene transferred onto a SiO2 substrate. (Srivastava A, et al, 2010)
High-resolution electron micrographs at the edges or wrinkles of graphene can be used to estimate the layer and size of graphene sheets.
Advantage: Simple and fast.
Figure 2. TEM images of folded edges for monolayer and bilayer graphene, respectively. (Meyer J.C, et al, 2007)
The single Lorentz-type second-order Raman peak (G' peak) is a simple and effective method for the determination of single-layer graphene. The number of graphene sheets can be characterized by the shape of the G'peak in the RS spectrum.
Figure 3. (a) Raman spectra of graphene with 1~4 layers; (b) Raman G' band of graphene with 1~4 layers. (Wu J.X, et al, 2014)
STM can provide atomic-level structural information on the surface of graphene. It can perfectly present the hexagonal honeycomb lattice structure of graphene. STM testing usually requires the substrate to be conductive, so graphene or silicon carbide epitaxial growth grown by metal-catalyzed CVD is the best sample for STM characterization.
Optical microscopy is limited to substrates that are significantly different from graphene in contrast.
Figure 5. Optical microscopy images of graphene with different layers. (Ni Z.H, et al, 2007)
Graphene, graphene oxide, reduced graphene oxide, CVD graphene, nanographene and etc.
The Standard we Follow:
GB/T 30544.13-2018 ISO/TS 80004-13:2017(en): Graphene and Related Two-dimensional (2D) Materials.
1. Alfa Chemistry laboratory adopts ISO/IEC17025 international laboratory management system.
2. Complete qualifications, a large number of instruments, and a strong scientific research team
3. The detection cycle is short and well designed experiment procedure.