| 研究実績の概要 |
In FY2020, we first established the lock-in Raman technique to greatly improve the temperature resolution of Raman thermometry. One of the biggest challenges of Raman thermometry is the relatively low temperature resolution, which is usually larger than 5 K. Here, we use modulated electrical current at a low frequency to heat the sample and simultaneously collect the Raman shifts that are linearly related to temperature. Then, we treat the Raman shifts data with fast Fourier transform and pick out the Raman shift with the same frequency as the heating current, so that the noises at other frequencies can be readily rooted out. Using this lock-in Raman thermography technique, we have successfully measured the thermal contact resistance between individual carbon fibers with high accuracy, the results of which will be submitted for publication soon. Second, we have fabricated single-layer graphene ribbons together with 10-terminal test devices for nanoscale heat transfer studies. Third, we have been testing scanning thermal microscopy (SThM) cantilever probes for nanoscale temperature mapping with ~50 nm resolution. Furthermore, we have established an in-situ nanoscale thermal measurement apparatus inside a scanning transmission electron microscope (STEM), which allows thermal conductivity measurement and internal structure observation at the same time.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
This project aims to establish a nanoscale thermal measurement platform that combines Raman thermometry, lock-in techniques, as well as AFM cantilever probes. We also aim to unveil new heat transfer physics by utilizing this platform. In FY2020, we have successfully established the lock-in Raman thermography technique, prepared single-layer graphene samples together with the measurement device for nanoscale heat conduction studies and started to test cantilever probes for thermal measurements. We have published several journal papers and given two invited talks relevant to this project. We will submit another two relevant papers for publication soon.
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| 今後の研究の推進方策 |
In FY2021, we will first establish techniques based on focused ion beam (FIB) and cantilever probes to introduce atomic-order nanostructures in single-layer graphene ribbons. Then, we will map the thermal properties of the graphene nanostructures using both lock-in Raman thermography and SThM. We aim to reveal new heat transfer physics through accurate nanoscale thermal measurements of high-quality nanoscale materials.
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