Overview
IEC TS 62607-6-16:2022 defines a standardized method to measure the carrier concentration of semiconducting two-dimensional (2D) materials using the field effect transistor (FET) method. The technical specification describes how to evaluate 2D carrier density from the voltage shift in transfer curves caused by a doping process. The FET test uses a three-terminal structure (source, drain, gate) where drain current is recorded while sweeping gate voltage at constant drain bias.
Key topics and requirements
- Measurement principle: Determine carrier concentration from the gate-voltage shift observed in transfer (Id–Vg) curves after an intentional doping or charge-injection step.
- Scope of applicability: Semiconducting 2D materials with a bandgap (e.g., transition metal dichalcogenides such as MoS2, MoTe2, WSe2, and black phosphorus). The method is not intended for pristine (semi-metallic) graphene but applies to graphenes with a bandgap (for example, graphene oxide).
- Sample preparation and FET fabrication: Guidance on preparing atomically thin samples and fabricating back-gated or other FET test structures suitable for accurate transfer-curve measurement.
- Equipment and ambient conditions: Defines measurement equipment description and recommended ambient/test conditions to ensure repeatability.
- Calibration and protocol: Calibration procedures for instruments and a step-by-step measurement protocol including how to obtain transfer curves and apply doping treatments.
- Data analysis: Procedures to extract carrier concentration from transfer curves, including treatment when the minimum-conductance (neutral) point is clear or unclear.
- Reporting requirements: Specifies required reporting elements - cover sheet, sample identification, measurement conditions, measurement-specific information, and final results.
- Informative annexes: Examples and test reports for Graphene FETs, graphene/hBN/MoS2 heterostructures, MoTe and WSe FET devices.
Applications and users
This technical specification is practical for:
- Materials scientists and device engineers characterizing 2D semiconductors.
- Nanomanufacturing and semiconductor process engineers implementing doping control.
- Metrology and test laboratories performing standardized electrical characterization.
- Quality control and R&D teams evaluating materials for nanoelectronic devices and sensors.
Key benefits include consistent, repeatable carrier concentration measurement, improved comparability across labs, and support for qualification of 2D-material technologies for electronic systems.
Related standards
- Part of the IEC TS 62607 series (“Nanomanufacturing – Key control characteristics”). Users should consult other parts of the series and the IEC webstore for complementary methods and related metrology guidance.