11:00 〜 11:15
▲ [10a-W371-8] Thermal conductivity measurement of suspended graphene by heat spreader method.
キーワード：Thermal phonon transport, Suspended graphene, Heat spreader method
Recent studies on the control and manipulation of thermal phonons show that specifically designed periodic arrays can reduce the thermal transport through a material by suppressing the transmission of a certain phonon wavelength. It has been observed by finite element method (FEM) simulations that, in case of graphene, periodic nanopores with sub-10 nm pitch exhibit phononic band gap in the low THz regime. Recently, periodic arrays of 3-4 nm sized pores have been successfully nanopatterned in suspended graphene by focused helium ion beam milling (HIM). In order to understand the influence of such periodic nanopores on the transmission of THz phonon, we are working on establishing a characterization platform to be able to measure practically the in-plane thermal conductivity of the suspended graphene. Heat spreader method uses microfabricated metal lines to create thermal gradient through the sample and resistance thermometry is used for in plane thermal transmission measurement. The process of fabrication and primary test execution of our thermal measurement system will be presented in this research work. The heaters and thermometers are fabricated on a silicon substrate using e-beam lithography (EBL). To separate graphene from the conducting metal layer, the transfer and patterning of an insulating layer of hexagonal boron nitride (hBN) is being carried out. Also, we are working on the transfer and patterning of the graphene layer for HIM milling. The optimization of lithography conditions is extremely crucial at this point. We are also conducting experiments to understand the operational condition of our thermal measurement system.