New metrological facilities for high temperature measurements of thermophysical properties have been recently developed by European National Metrology Institutes (NMIs). This work, performed in the framework of the joint research project “MetroFission”, aims to provide reliable measurements up to 2000 for materials having thermal properties similar to those required for design of new generations of fission reactors. This will enable to improve the traceability to the International System of Units (SI) of measurements performed by nuclear research laboratories. The validation of these reference apparatuses was done at high temperature by measuring the thermal diffusivity and normal spectral emissivity of an isostatic graphite and pure tungsten.

Thermal management is a key issue for the downsizing of electronic components in order to optimise their performance. These devices incorporate more and more nanostructured materials, such as thin films or nanowires, requiring measurement techniques suitable to characterise thermal properties at the nanoscale, such as Scanning Thermal Microscopy (SThM). In active mode, a hot thermoresistive probe scans the sample surface, and its electrical resistance R changes as a function of heat transfers between the probe and sample. This paper presents the measurement and calibration protocols developed to perform quantitative and traceable measurements of thermal conductivity k using the SThM technique, provided that the heat transfer conditions between calibration and measurement are identical, i.e., diffusive thermal regime for this study. Calibration samples with a known k measured at the macroscale are used to establish the calibration curve linking the variation of R to k. A complete assessment of uncertainty (influencing factors and computational techniques) is detailed for both the calibration parameters and the estimated k value. Outcome analysis shows that quantitative measurements of thermal conductivity with SThM (with an uncertainty value of $10\%$) are limited to materials with low thermal conductivity ($k<10\mathrm{W}{\mathrm{m}}^{-1}{\mathrm{K}}^{-1}$).

Although graphene promises a wide range of applications, large-scale production of this material remains complex. One very common way of obtaining graphene is through a reduction in graphene oxide (GO). In order to fully control this production process, it is necessary to obtain data from different techniques, but a comprehensive characterization methodology and associated metrology are currently lacking. Here, we propose tools for substrate selection (in this study, the most appropriate were silicon and silicon dioxide on silicon) and precautions to be taken when setting up a correlative metrology method integrating atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman microscopy/spectroscopy, scanning microwave microscopy (SMM) and scanning thermal microscopy (SThM). Indeed, in order to obtain reliable data for each of these techniques applied to a unique graphene oxide flake, a strategy must be developed and could be implemented to monitor the reduction in GO. Emphasis was placed on the choice of the substrate and on the possible degradations generated by each of the techniques employed, and a running sequence was determined.