Abstract
Air-suspended Si nanowires with various widths and a phononic crystal nanostructure with a period of 300 nm were fabricated on an SOI wafer by electron beam lithography and their thermal conductivities were measured at room temperature. We observed lower thermal conductivities for narrower nanowires. The reduction of the thermal conductivities mainly stems from the increase of the surface scattering rate. On the other hand, in the phononic crystal nanostructure, we observed lower thermal conductivity compared with a nanowire with a width equal to the narrowest part of the PnC structure. Therefore, the phononic effect may also play some role in heat transfer in the PnC structure in addition to the increase of the surface scattering.
