  We theoretically investigate thermal conductivity in silicon nanomeshes using
Monte Carlo simulations of phonon transport. Silicon membranes of 100nm
thickness with randomly located pores of 50nm diameter are considered. The
effects of material porosity and pore surface roughness are examined. Nanomesh
porosity is found to have a strong detrimental effect on thermal conductivity.
At room temperature, a porosity of 50% results in ~80% reduction in thermal
conductivity. Boundary roughness scattering further degrades thermal
conductivity, but its effect is weaker. Thermal transport can additionally be
affected by the specific arrangement of the pores along the transport
direction.
