Thermal conductivity of large-diameter nonporous and porous SiNW arrays. (a) Thermal conductivity of nonporous and porous SiNW arrays of large diameters as a function of doping concentrations. TEM images show the relative porosity for Ag-MACE SiNW arrays fabricated with doping concentrations of (b) 1014, (c) 1016, and (d) 1018 cm−3. The scale bars on the TEM and inset TEM images are 5 and 200 nm, respectively. The uncertainty bar for the MACE nanowires with a doping concentration of 1018 cm−3 is on the order of the data point marker size.