IEC TS 62607-6-12:2024

Nanomanufacturing - Key Control Characteristics - Part 6-12: Graphene - Number of layers: Raman spectroscopy, optical reflection

IEC TS 62607-6-12:2024 establishes a standardized method to determine the key control characteristic
- number of layers
for films consisting of graphene by
- Raman spectroscopy and
- optical reflection.
Criteria for the determination of the number of layers are the G-peak integrated intensity and the optical contrast. Both methods enable to distinguish between graphene and multilayer graphene. However, neither method on its own nor the combination of the two enable a determination of the number of layers in all possible cases (especially regarding all possible stacking angles). But the comparison of the values deduced by each method allows to discriminate whether the determined number of layers is correct and can be specified or not.
- The method is applicable to exfoliated graphene and graphene grown on or transferred to a substrate with a small defect density, low surface contamination (e.g. transfer residue) and number of layers up to 5.
- The method is suitable for the following substrates:
a) glass (soda lime glass or similar with a refractive index between 1,45 and 1,55 at 532 nm);
b) oxidized silicon (SiO2 on silicon, with a SiO2 thickness of 90 nm ± 5 nm).
- The spatial resolution is in the order of 1 µm given by the spot size of the exciting laser.

General Information

• Status: Published
• Publication Date: 27-Jun-2024
• ICS: 07.120 - Nanotechnologies
• Technical Committee: TC 113 - Nanotechnology for electrotechnical products and systems
• Drafting Committee: WG 8 - TC 113/WG 8
• Current Stage: PPUB - Publication issued
• Start Date: 17-Jul-2023
• Completion Date: 28-Jun-2024

Standards Content (Sample)

IEC TS 62607-6-12 ®
Edition 1.0 2024-06
TECHNICAL
SPECIFICATION
Nanomanufacturing – Key Control Characteristics –
Part 6-12: Graphene – Number of layers: Raman spectroscopy, optical reflection

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IEC TS 62607-6-12 ®
Edition 1.0 2024-06
TECHNICAL
SPECIFICATION
Nanomanufacturing – Key Control Characteristics –

Part 6-12: Graphene – Number of layers: Raman spectroscopy, optical reflection

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 07.120  ISBN 978-2-8322-9292-1

– 2 – IEC TS 62607-6-12:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
3.1 General terms . 9
3.2 Graphene related terms . 9
3.3 Key control characteristics measured in accordance with this document . 11
3.4 Terms related to the measurement method described in this document . 12
4 General . 13
4.1 Measurement principle . 13
4.2 Sample preparation method . 14
4.3 Measurement environment . 14
4.4 Description of test equipment . 14
4.5 Calibration standards . 16
4.5.1 Raman reference sample . 16
4.5.2 Reflection reference sample . 16
5 Measurement procedure . 17
5.1 Calibration of test equipment . 17
5.1.1 Raman spectrometer . 17
5.1.2 Optical reflection setup . 17
5.2 Description of the measurement procedure . 17
5.3 Sampling plan . 17
5.4 Measurement accuracy . 17
6 Data analysis and interpretation of results . 18
6.1 Analysis of the Raman spectra . 18
6.2 Analysis of the reflectance measurement . 19
6.3 Interpretation of the combined measurement . 21
7 Test report . 22
7.1 General . 22
7.2 Sample identification . 22
7.3 Test conditions . 23
7.4 Measurement specific information . 23
7.5 Test results . 23
Annex A (informative) Format of the test report . 24
Annex B (informative) Sampling plan . 27
B.1 General . 27
B.2 Sampling plan depending on substrate geometry . 28
B.2.1 Circular substrates . 28
B.2.2 Rectangular substrates . 29
B.2.3 Irregular shaped substrates . 30
B.2.4 Coordinate system . 30
Bibliography . 32

Figure 1 – Raman spectra of HOPG (top), pristine graphene (middle) and defective
few-layer graphene (bottom) . 14

Figure 2 – Schematic illustration of the Raman and reflectance setup used for the
described graphene classification . 16
Figure 3 – Number of layers as a function of G-peak integrated intensity on glass (top)
and on 90 nm ± 5 nm SiO on Si (bottom) . 19
Figure 4 – Number of layers as a function of the optical contrast on glass (top) and on
90 nm ± 5 nm SiO on Si (bottom) . 20
Figure 5 – Decision criteria regarding the number of layers . 22
Figure B.1 – Schematic of sample plan for circular substrates . 28
Figure B.2 – Schematic of sample plan for square substrates . 29
Figure B.3 – Example sampling plan for irregular sample . 30
Figure B.4 – Coordinate system applied to the measurement results in the test report . 31

Table 1 – Number of layers decision table A, if the estimates of N and N agree . 21
G C
Table 2 – Number of layers decision table B, if the estimates are between numbers.
Exact number of layers cannot be specified but a range of N . 21
Table 3 – Number of layers decision table C, if the values of N are slightly lower than
G
N . . 21
C
Table A.1 – Product identification . 24
Table A.2 – General material description . 24
Table A.3 – Measurement related information . 24
Table A.4 – Measurement results . 25
Table A.5 – Colour map of KCC . 26
Table B.1 – Sampling plan for circular substrates . 28
Table B.2 – Sampling plan for square sample . 29

– 4 – IEC TS 62607-6-12:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NANOMANUFACTURING –
KEY CONTROL CHARACTERISTICS –
Part 6-12: Graphene – Number of layers:
Raman spectroscopy, optical reflection

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