Measurement of heat diffusion across fuzzy tungsten layer

Heat diffusion across the fuzzy nanostructured tungsten (W) layer formed by helium plasma irradiation was measured using a pulsed light heating thermoreflectance method. By observing the heat diffusion across the nanostructured tungsten layer with a short (1 ns) laser pulse heating, the averaged thermal conductivity of the nanostructured layer was deduced to be ∼1.5 W/mK, which is ∼1% or less of that of pure (ideal) W.