| 研究実績の概要 |
In FY2019, we first completed the thermoelectric measurement of the ~40nm-wide and ~250nm-long graphene nanoribbon samples using the 8-terminal method repeatedly at different temperatures, and fully revealed the mechanisms of phonon and electron transport in this nanostructure. We confirmed a boost of thermoelectric figure of merit for graphene in these suspended ~40nm-wide and ~250nm-long samples，the results of which were summarized and published in ACS Nano in this year.
Second, we improved the measurement method and developed a 10-terminal device that can comprehensively measure the thermoelectric properties of graphene nanostructures with a higher accuracy. Finite-element simulations were carried out to optimize the device structure and the circuit wiring module was reformed and validated.
Third, we fabricated as-grown suspended graphene nanoribbons with narrower widths that were integrated with the new 10-terminal device. The sensors of the nanoscale 10-terminal device were well-calibrated. However, it was rather difficult to fabricate beautiful samples when we changed the sample sizes because of the sensitive synthesis conditions. Although we have not obtained reliable thermoelectric data of graphene with varied nanostructures, we have established the experimental approaches and can hopefully reveal the size and structure effects in the future.
|
