Significant reduction of graphene thermal conductivity by phononic crystal structure

Reduction of Thermal Conductivity by Nanoscale 3D Phononic Crystal

We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal cond...

Thermal conductivity reduction in phononic nanomesh structures

Device Fabrication All devices were prepared on silicon-on-insulator (SOI; Soitec Inc.) wafers. The SOI wafers were pre-doped by thermally diffusing spin-on-dopant (Boron A; Filmtronics, Inc.) with rapid thermal annealing (RTA) at 820C for 3 minutes. The resulting sheet resistance indicates a doping concentration of 2x10 cm, with the thickness of the silicon epilayer determined by atomic force...

Reduction in the thermal conductivity of single crystalline silicon by phononic crystal patterning.

Phononic crystals (PnCs) are the acoustic wave equivalent of photonic crystals, where a periodic array of scattering inclusions located in a homogeneous host material causes certain frequencies to be completely reflected by the structure. In conjunction with creating a phononic band gap, anomalous dispersion accompanied by a large reduction in phonon group velocities can lead to a massive reduc...

Significant thermal conductivity enhancement for nanofluids containing graphene nanosheets

Mechanism of thermal conductivity reduction in few-layer graphene