IEC TS 62607-6-28:2025

IEC TS 62607-6-28:2025, which is a Technical Specification, establishes two standardized methods to determine the key control characteristic
• number of layers
for graphene layers by
• Raman spectroscopy.
This document presents two complementary methods for determining the number of layers in graphene-related products: Method A, which analyzes the lineshape of the 2D-peak in the Raman spectrum, and Method B, which measures the Raman intensity from the underlying silicon substrate. The two methods can be employed individually but combining both methods enhances accuracy and extends the detection range for the number of layers and stacking configurations.
- The method is intended to be used for graphene layers prepared by mechanical exfoliation, but also can be used with care for other high quality graphene layers, such as graphene layers prepared by chemical vapor deposition.
- The method can be used for graphene layers with AB and ABC stacking on a substrate. Its lateral size should be at least 2 µm.
- Method A is effective for AB stacked graphene up to 4 layers but becomes less reliable with more layers due to peak overlap.
- Method B can detect up to 10 layers in AB and ABC stacking but oxidized silicon substrate (SiO2 on silicon substrate) is required.
- The comparison of Method A and Method B can be found in Annex A.