2018 Fiscal Year Annual Research Report
Thermal energy trap by a surface phonon polariton cavity
| Project/Area Number |
18F18725
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| Research Institution | The University of Tokyo |
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Principal Investigator |
野村 政宏 東京大学, 生産技術研究所, 准教授 (10466857)
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| Co-Investigator(Kenkyū-buntansha) |
GLUCHKO SERGEI 東京大学, 生産技術研究所, 外国人特別研究員
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| Project Period (FY) |
2018-07-25 – 2020-03-31
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| Keywords | phonon polariton / phonon engineering |
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| Outline of Annual Research Achievements |
a. I've been working on the improvement of the sensitivity of our micro time-domain thermoreflectance (TDTR) set-up in order to sense one order of magnitude smaller temperature variations of the sample as well as changing the data analysis. I have also fabricated samples and studied the thermal conductivity of the phononic crystal with strongly asymmetric holes as well as phonon ballisticity in nanowires. These two projects provided the knowledge to design an experiment that has enough sensitivity to measure the Surface Phonon Polaritonic (SPhP) thermal conductivity of fully suspended thin dielectric membranes. For that, we required installing a new vacuum chamber that can support temperatures up to 800K as well as developing a new samples fabrication method based on fully suspended membrane technology. The article where we finalize these results is currently under preparation.
b. I have also supervised a master student where we have developed a new fabrication technique of maskless lowcost nanocones fabrication and thermal measurements.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
No big problem so far and the project is going along the plan.
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| Strategy for Future Research Activity |
We plan to fabricate an SPhP cavity using the same fabrication technique that we have developed for our previous study and measure the SPhPs passive concentration by an improved version of TDTR technique. This requires the following steps:
a. Finalizing the sample design.
b. Electron beam lithography and electron beam physical vapor deposition combination followed by focused ion beam etching of fully suspended SiN membranes.
c. TDTR measurements of the samples with two different cryostats that would provide the data in the temperature range from 4K to 750K
d. Data analysis and finalizing the results.
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