Comparison between NIST Graphene and AIST GaAs Quantized Hall Devices

Area of Science:

• Metrology
• Condensed Matter Physics
• Materials Science

Background:

• Quantized Hall Resistance (QHR) is a fundamental standard for electrical resistance.
• Graphene-based QHR devices offer potential advantages over traditional Gallium Arsenide (GaAs) devices.
• Accurate and reliable resistance metrology is crucial for scientific and industrial applications.

Purpose of the Study:

• To compare the performance of graphene QHR devices with established GaAs QHR devices and a 100 Ω standard resistor.
• To evaluate a novel functionalization method for tuning graphene QHR devices.
• To demonstrate the suitability of graphene QHR devices for inter-laboratory resistance comparisons.

Main Methods:

• Graphene QHR devices manufactured at NIST were compared to GaAs QHR devices and a 100 Ω standard resistor at AIST.
• Electron density of graphene devices was adjusted using a functionalization method followed by annealing.
• Resistance measurements were performed at low magnetic flux densities (4 T to 6 T).

Main Results:

• Graphene QHR measurements of the 100 Ω resistor agreed within 5 nΩ/Ω with GaAs-based measurements.
• The functionalization method enabled consistent tunability of graphene QHR devices.
• Graphene devices operated effectively at reduced magnetic flux densities after electron density adjustment.

Conclusions:

• Graphene QHR devices provide a viable and accurate alternative to GaAs devices for resistance metrology.
• The demonstrated functionalization method offers a predictable and simple way to tune graphene QHR devices.
• Graphene QHR devices facilitate easier resistance comparison measurements between National Metrology Institutes.