Thermal conductivity of sintered porous silicon films

We measure the thermal diffusivity, thermal conductivity, and the volumetric heat capacity of sintered porous silicon at room temperature using a non-contact method based on lock-in thermography. Free standing single-crystal thin film samples with porosities between 27% and 66% are analyzed. The observed thermal conductivities range from 21 to 2.3 W/(m K) and decrease with increasing porosity. Effective medium theory calculations describe the dependence of the thermophysical properties on the sample porosity.