The continuing progress in miniaturization of silicon microelectronic and photonic devices is causing cooling of the device structures to become increasingly challenging. Conventional heat transport in bulk materials is dominated by acoustic phonons, which are quasiparticles that represent the material’s lattice vibrations, similar to the way that photons represent light waves. Unfortunately, this type of cooling is reaching its limits in these tiny structures.
However, surface effects become dominant as the materials in nanostructured devices become thinner, which means that surface waves may provide the thermal transport solution required. Surface phonon-polaritons (SPhPs) — hybrid waves composed of surface electromagnetic waves and optical phonons that propagate along the surfaces of dielectric membranes — have shown particular promise, and a team led by researchers from the Institute of Industrial Science, the University of Tokyo has now demonstrated and verified the thermal conductivity enhancements provided by these waves.
“We generated SPhPs on silicon