The EC has identified key emerging technologies with transformative potential for industry. Graphene and related 2D materials are prominent examples and the EC’s Graphene Flagship aims to take these materials from the laboratory into society.

The Quantum Hall resistance standard (QHRS) is a universal standard for electrical resistance but requires demanding experimental conditions such as high magnetic fields and cryogenic temperatures. Graphene’s 2D hexagonal-lattice structure imparts the electrical properties required for a more practical QHRS. However, its properties depend on the substrate on which it is deposited and the inability to grow large areas has limited its use. Materials such as ‘single layered two-dimensional Dirac covalent- and metal- organic frameworks’ (2D-COF/MOFs) are alternative QHRS candidates but have not been characterised to the level for use in metrology or in industrial products.

This project will develop graphene-like hexagonal structured 2D-COF/MOFs from organic ligands and the chemistry, morphology and electronic properties ‘tuned’ in an atomically precise and scalable manner. The 2D-COF/MOFs will then be characterised in relation to sample area and the substrate used prior to integration into QHRS devices. Measurements will then be performed to compare the performance of these to graphene and other materials used in QHRS. By benchmarking the use of 2D-COF/MOFs as a replacement for graphene this project will take the first steps to realising the use of these materials as primary electrical standards, supporting the aims of the Graphene flagship. It will also potentially impact on industries linked with 2D materials including solar energy conversion, semi-conductors and optoelectronics.

The overall objective of the project will be to assess (benchmark) the potential of 2D organic- and metal-organic frameworks for realising the QHRS. The specific objectives of the project are:

1. To develop single layered two-dimensional Dirac covalent- and metal- organic frameworks (2D-COF/MOFs) in which graphene-like hexagonal structures are obtained from trigonal organic ligands. The chemistry, morphology and electronic properties of 2D-COF/MOFs will be tuned in an atomically precise and scalable manner.
2. To perform traceable multi-scale characterization on the 2D-COF/MOFs samples. Specifically, to characterize their electrical properties as a function of sample’s area and the nature of the employed substrate (prior to and after integration into QHRS devices).
3. To perform QHE measurements on the manufactured devices and to assess the potential of 2D-COF/MOFs materials for realising the QHRS. Specifically, to benchmark QHRS devices based on these samples vs those based on graphene and AlGaAs/GaAs hetero-structures.
4. To assure European leadership on the research of novel class of 2D materials by establishing the research capabilities, appropriate protocols, quality schemes and traceability and facilitate the take up of the technology and measurement infrastructure developed in the project by the metrology community and in the development of emerging technologies such as solar energy conversion, sensing, membranes, optoelectronics, spintronics, etc. To disseminate the results to stakeholders (within and beyond the metrology community) in order to enable research cooperation that can be sustained in the long term.