IEC TS 62607-6-11:2022

Nanomanufacturing - Key control characteristics - Part 6-11: Graphene - Defect density: Raman spectroscopy

IEC TS 62607-6-11:2022(EN) establishes a standardized method to determine the key control characteristic
• defect density nD
of graphene films grown by chemical vapour deposition as well as exfoliated graphene flakes by
• Raman spectroscopy

General Information

• Status: Published
• Publication Date: 07-Feb-2022
• ICS: 07.120 - Nanotechnologies
• Technical Committee: TC 113 - Nanotechnology for electrotechnical products and systems
• Drafting Committee: PT 62607-6-11 - TC 113/PT 62607-6-11
• Current Stage: PPUB - Publication issued
• Start Date: 08-Feb-2022
• Completion Date: 01-Mar-2022

Overview

IEC TS 62607-6-11:2022 defines a standardized Raman spectroscopy method to quantify the defect density (nD) of graphene used in nanomanufacturing. The Technical Specification applies to graphene films grown by chemical vapour deposition (CVD) and to exfoliated graphene flakes on substrates. Defect density is derived from the Raman intensity ratio I(D)/I(G) based on the three-stage amorphization model for carbon materials. The method covers the practical measurement chain (sample preparation, instrumentation, calibration, ambient conditions), sampling and reporting requirements, and data interpretation for stage‑1 disorder.

Key topics and requirements

• Measurement principle: Defect density is calculated from the Raman D‑peak and G‑peak intensity ratio I(D)/I(G) using the three‑stage classification for graphene lattice disorder.
• Applicable range: The method is intended for samples with I(D)/I(G) in the range 0.1 to ~3, corresponding to stage 1 (graphene → nanocrystalline graphene). For 514 nm excitation (2.41 eV) this approximates a defect density range of about 2.46 × 10^10 cm⁻² to 7.39 × 10^11 cm⁻².
• Spatial resolution: Determined by the laser spot size, typically on the order of 1 µm for micro‑Raman setups.
• Data processing: Guidance on peak fitting, calibration, alignment and how to convert I(D)/I(G) into inter‑defect distance (L) and defect density.
• Procedure elements: Sample preparation, description of test equipment, ambient condition specifications, measurement accuracy, sampling plan and standardized test‑report format.
• Limitations and complementarity: The method is complementary to IEC 62607‑6‑6 and is intended when a visible D‑peak is present within the stated I(D)/I(G) range.

Applications and users

• Quality control in graphene production (CVD manufacturers): routine monitoring of defect levels to ensure product consistency.
• Device fabrication and process development: evaluating whether material quality meets requirements for high‑mobility electronic, photonic or sensing devices.
• Research and development: reproducible characterization of defect evolution, doping and damage studies.
• Test labs and certification bodies: standardized reporting to support comparability across suppliers and batches.

Practical benefits include reliable classification of graphene quality, traceable defect‑density metrics for material selection, and a standardized basis for correlating structural disorder with electronic performance.

Related standards

• IEC TS 62607 series - Nanomanufacturing: Key control characteristics (series context).
• IEC 62565‑3‑1 - blank detail specification referencing defect density as a key control characteristic.
• IEC 62607‑6‑6 - complementary Raman method for cases outside the I(D)/I(G) range covered here.

Keywords: IEC TS 62607-6-11, graphene defect density, Raman spectroscopy, I(D)/I(G), CVD graphene, exfoliated graphene, nanomanufacturing, inter-defect distance, three-stage amorphization.

Standards Content (Sample)

IEC TS 62607-6-11 ®
Edition 1.0 2022-02
TECHNICAL
SPECIFICATION
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inside
Nanomanufacturing – Key control characteristics –
Part 6-11: Graphene – Defect density: Raman spectroscopy
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IEC TS 62607-6-11 ®
Edition 1.0 2022-02
TECHNICAL
SPECIFICATION
colour
inside
Nanomanufacturing – Key control characteristics –

Part 6-11: Graphene – Defect density: Raman spectroscopy

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 07.120 ISBN 978-2-8322-1071-9

– 2 – IEC TS 62607-6-11:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
3.1 General terms . 8
3.2 Key control characteristics measured in accordance with this document . 9
3.3 Terms related to the measurement method described in this document . 9
4 General . 10
4.1 Measurement principle . 10
4.2 Sample preparation method . 11
4.3 Description of test equipment . 11
4.4 Calibration standards, alignment and peak fitting . 12
4.5 Ambient conditions. 12
5 Measurement procedure . 12
5.1 Description of the measurement procedure . 12
5.2 Measurement accuracy . 13
6 Data analysis and interpretation of results . 13
7 Sampling plan . 14
8 Test report . 14
8.1 General . 14
8.2 Sample identification . 14
8.3 Test conditions . 14
8.4 Measurement specific information . 15
8.5 Test results . 15
Annex A (informative) Format of the test report . 16
Annex B (normative) Sampling plan . 19
B.1 General . 19
B.2 Sampling plan depending on substrate geometry . 19
B.2.1 Circular substrates . 19
B.2.2 Square substrates . 20
B.2.3 Irregular shaped substrates . 21
B.2.4 Coordinate system . 21
Annex C (informative) Recommendations for wavelengths depending on substrate . 23
Annex D (informative) Application examples . 24
D.1 Raman spectra within stage 1 of the three-stage model for amorphization
with increasing defect density . 24
D.2 Calculation of the defect density from I(D)/I(G) on doped graphene . 25
D.3 Estimation of the defect level of a doped sample. 26
Bibliography . 27

Figure 1 – Three-stage classification to describe graphene lattice disorder . 6
Figure 2 – Raman spectra of pristine (top) and defective graphene (bottom) [1] . 10
Figure 3 – Schematic of micro-Raman setup used for graphene characterization . 12
Figure 4 – E [I(D)/I(G)] as a function of L . 14
L D
Figure B.1 – Schematic of sample plan for circular substrates . 19
Figure B.2 – Schematic of sample plan for square substrates . 20
Figure B.3 – Example sampling plan for irregular sample . 21
Figure B.4 – Coordinate system applied to the measurement results in the test report . 22
Figure D.1 – Representative Raman spectra of ion-bombarded graphene samples. . 24
Figure D.2 – I(D)/I(G) as a function of charge carrier concentration . 25
Figure D.3 – Raman spectra of a defective graphene sample at doping level of a) E ≤
F
100 meV and b) E ~ 500 meV [11] . 26
F
Table A.1 – Product identification (in accordance with IEC 62565-3-1) . 16
Table A.2 – General material description (in accordance with IEC 62565-3-1). 16
Table A.3 – Measurement related information . 17
Table A.4 – Measurement results . 17
Table A.5 – Colour map of KCC . 18
Table B.1 – Sampling plan for circular substrates . 20
Table B.2 – Sampling plan for square sample . 21
Table C.1 – Recommended laser wavelength depending on used substrate . 23

– 4 – IEC TS 62607-6-11:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NANOMANUFACTURING – KEY CONTROL CHARACTERISTICS –

Part 6-11: Graphene – Defect density: Raman spectroscopy

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC TS 62607-6-11 has been prepared by IEC technical committee 113, Nanotechnology for
electrotechnical products and systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
113/591/DTS 113/626/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.

A list of all parts in the IEC TS 62607 series, published under the general title
Nanomanufacturing – Key control characteristics, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – IEC TS 62607-6-11:2022 © IEC 2022
INTRODUCTION
Graphene is a single layer of carbon atoms arranged in a honeycomb lattice. Due to its
outstanding properties such as high mobility and flexibility, it has high potential for future
applications. Structural defects, e.g. anything that changes the regularity of the lattice, have a
huge influence on the properties of graphene, especially the mobility. For most electronic
applications having high quality, almost defect-free graphene is crucial. Thus the defect density
as a measure of the structural quality of graphene is a key control characteristic of graphene.
Raman spectroscopy is one of the most widely used characterization techniques in carbon
science and technology. There are two main peaks in the Raman spectrum of graphene, the
−1 −1
G peak located around 1 580 cm and the 2D peak located around 2 680 cm for an excitation
wavelength of 514 nm. Raman spectroscopy can be used to extract valuable information about
the sample properties such as the number of layers, doping level, amount and type of strain as
well as defect density [1] . Quantifying defects in graphene is crucial for both gaining insight in
fundamental properties and for applications. Defects strongly affect the mobility of graphene. It
is thus important for device fabrication and optimization as well as a quality check to know the
defect density in a sample.
Disorder of the graphene lattice can be described [2] in a three-stage classification, leading
from graphite to amorphous carbons, that allows to simply assess all the Raman spectra of
carbons:
• Stage 1: graphene to nanocrystalline graphene.
• Stage 2: nanocrystalline graphene to low-sp amorphous carbon.
3 3
• Stage 3: low-sp amorphous carbon to high-sp amorphous carbon.
This classification is illustrated in Figure 1.

Figure 1 – Three-stage classification to describe graphene lattice disorder

—————————
Numbers in square brackets refer to the Bibliography.

NANOMANUFACTURING – KEY CONTROL CHARACTERISTICS –

Part 6-11: Graphene – Defect density: Raman spectroscopy

1 Scope
This part of IEC TS 62607 establishes a standardized method to determine the key control
characteristic
• defect density n
D
of graphene films grown by chemical vapour deposition as well as exfoliated graphene flakes
by
• Raman spectroscopy.
The defect density n is derived from the intensity ratio of the D-peak and the G-peak I(D)/I(G)
D
in the Raman spectrum based on the three-stage model for amorphization.
• The classification helps manufacturers to classify their material quality and customers to
provide an expectation of the electronic performance of the classified graphene and more
specifically to decide whether or not the graphene material quality is potentially suitable for
various applications.
• The defect density n determined in accordance with this document is listed as a key control
D
characteristic in the blank detail specification for graphene IEC 62565-3-1. The inter-defect
distance L can be calculated from the defect density n and is an equivalent measure of
D D
defects in the graphene lattice.
• The method is applicable for exfoliated graphene and graphene grown on or transferred to
a substrate with I(D)/I(G) in the range of 0,1 to 3, which corresponds to a defect density of
10 −1 11 −2
2,46 × 10 cm up to 7,39 × 10 cm for an excitation energy of 2,41 eV (514 nm),
corresponding to stage 1 of the three-stage model for amorphization.
• The spatial resolution is in the order of 1 µm given by the spot size of the exciting laser.
• The method is complementary to the method described in IEC 62607-6-6 and is used if the
Raman spectrum shows a visible D-peak with an intensity ratio I(D)/I(G) in the range of 0,1
to around 3.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

– 8 – IEC TS 62607-6-11:2022 © IEC 2022
3.1 General terms
3.1.1
key control characteristic
KCC
key performance indicator
material property or intermediate product characteristic which can affect safety or compliance
with regulations, fit, function, performance, quality, reliability or subsequent processing of the
final product
Note 1 to entry: The measurement of a key control characteristic is described in a standardized measurement
procedure with known accuracy and precision.
Note 2 to entry: It is possible to define more than one measurement method for a key control characteristic if the
correlation of the results is well-defined and known.
3.1.2
chemical vapour deposition
CVD
deposition of a solid material by chemical reaction of a gaseous precursor or mixture of
precursors, commonly initiated by heat on a substrate.
[SOURCE: ISO/TS 80004-13:2017, 3.2.1.1]
3.1.3
defect
local deviation from regularity in the crystal lattice of a 2D material
[SOURCE: ISO/TS 80004-13:2017, 3.4.1.1]
3.1.4
graphene
graphene layer
single-layer graphene
monolayer graphene
single layer of carbon atoms with each atom bound to three neighbours in a honeycomb
structure
Note 1 to entry: It is an important building block of many carbon nano-objects.
Note 2 to entry: As graphene is a single layer, it is also sometimes called monolayer graphene or single-layer
graphene and abbreviated as 1LG to distinguish it from bilayer graphene (2LG) and few-layer graphene (FLG).
Note 3 to entry: Graphene has edges and can have defects and grain boundaries where the bonding is disrupted.
[SOURCE: ISO/TS 80004-13:2017, 3.1.2.1]
3.1.5
point defect
<2D material> defect that occurs only at or around a single lattice point of a 2D material
Note 1 to entry: Point defects generally involve at most a few missing, dislocated or different atoms creating a
vacancy or vacancies, extra atoms (interstitial defects) or replaced atoms.
[SOURCE: ISO/TS 80004-13:2017, 3.4.1.2]
3.1.6
roll-to-roll production
R2R production
<2D material> CVD growth of 2D material upon a continuous substrate that is processed as a
rolled sheet, including transfer of 2D material to a separate substrate

[SOURCE: ISO 80004-13:2017, 3.2.1.2]
3.2 Key control characteristics measured in accordance with this document
3.2.1
defect density
n
D
number of point defects per area
−2
Note 1 to entry: The unit of the defect density is cm .
Note 2 to entry: The defect density is a key control characteristic to describe local deviations from regularity in the
crystal lattice of graphene according to stage 1 of the three-stage model for amorphization.
−4 2
Note 3 to entry: The defect density is related to the mean distance between point defects L by n = 10 /πL .
D D D
3.2.2
inter-defect distance
L
D
mean distance between point defects in the crystal lattice of graphene
Note 1 to entry: The unit of the inter-defect distance is the nanometre (nm).
Note 2 to entry: The inter-defect distance is a key control characteristic to describe local deviations from regularity
in the crystal lattice of graphene according to stage 1 of the three-stage model for amorphization.
−4 2
Note 3 to entry: The defect density n is related to the inter-defect distance by n = 10 /πL .
D D D
3.3 Terms related to the measurement method described in this document
3.3.1
2D peak
second order Raman peak related to a two-phonon process located at approximately twice the
frequency of the D peak
Note 1 to entry: As well as the D peak the 2D peak is also dispersive with wavelength. The position of the 2D peak
changes strongly with laser energy
Note 2 to entry: The 2D peak is always present in the Raman spectrum of graphene and does not need defects to
be activated.
3.3.2
D peak
defect activated Raman peak related to lattice breathing modes in six-carbon rings away from
the centre of the Brillouin zone
−1 −1
Note 1 to entry: The D peak is located between 1 270 cm and 1 450 cm depending on the wavelength of the
−1
excitation laser. The dispersion with wavelength is around 50 cm /eV.
Note 2 to entry: The D peak is most intense at defective graphene lattices and disappears for perfect monolayer
crystals. Therefore it is often called the disorder band.
3.3.3
D′ peak
−1
defect activated Raman peak in the spectrum of graphene located around 1 620 cm
originating from scattering away from the Brillouin zone centre.
3.3.4
G peak
−1
Raman peak related to in-plane motion of the carbon atoms located near 1 580 cm originating
from scattering at the centre of the Brillouin zone
Note 1 to entry: The G peak can be observed in pristine graphene and does not need lattice defects to occur.

– 10 – IEC TS 62607-6-11:2022 © IEC 2022
3.3.5
laser spot size
diameter of circular laser spot on sample when sample is in focus
Note 1 to entry: Diameter is measured at the full width at half maximum (FWHM) of the intensity distribution.
3.3.6
Raman spectroscopy
spectroscopy in which the radiation emitted from a sample illuminated with monochromatic
radiation is characterized by an energy loss or gain arising from rotational, vibrational or phonon
excitations
[SOURCE: ISO/TS 80004-13:2017, 3.3.1.6]
4 General
4.1 Measurement principle
Raman spectroscopy is very sensitive to defects. In addition to the G and 2D peaks, which are
always present in the Raman spectrum of graphene, Figure 2 top spectrum, additional defect
activated peaks appear in the Raman spectrum of defective graphene. As shown in the bottom
spectrum in Figure 2, the Raman spectrum of defective graphene changes as follows: the defect
activated D, D′ peaks and their combination D+D′ appear.

Figure 2 – Raman spectra of pristine (top) and defective graphene (bottom) [1]
In this document we focus on stage 1 of the three-stage model for amorphization, the most
relevant when considering the vast majority of publications dealing with graphene production,
processing and applications. In stage 1 the intensity of the D peak increases for increasing
amount of defects. The intensity ratio of the D peak to the G peak, I(D)/I(G), is then directly
linked to the inter-defect distance and the defect density in the sample.
The inter-defect distance L can be expressed by [3]:
D
−1

I D
4,3×10 ( )
L = (1)

D
I G
E ( )

L 
E is the laser excitation energy in electronvolts (eV) (E = 2,41 eV at λ = 514 nm). By
L L
considering point defects, separated from each other by L in nm, Formula (1) can be restated
D
14 2
−2
nL= 10 π
in terms of defect density, n , in cm , given by , as [3]:
DD
D
I D
( )
nE7,3×10
(2)
DL
I G
( )
11 −2
This relation is valid for L ≥ 10 nm corresponding to n ≤ 3,2 × 10 cm (stage 1). Note that
D D
Formula (1) and Formula (2) are limited to Raman-active defects. Perfect zig-zag edges [4][5],
charged impurities [6][7], intercalants [8], and uniaxial and biaxial strain [9][10] do not generate
a D peak in the Raman spectrum of graphene [1].
Examples for Raman spectra for graphene with defects are given in Annex D. Clause D.1 shows
spectra for undoped graphene and an inter-defect distance between 2 nm and 24 nm. The
influence of doping is described in Clauses D.2 and D.3. Clause D.2 also provides the
modification of Formula (1) and Formula (2) for doped graphene.
4.2 Sa
...