In physical processes, metal nanoparticles are generally synthesized
by evaporation–condensation, which could be carried out
using a tube furnace at atmospheric pressure. The source material
within a boat centered at the furnace is vaporized into a
carrier gas. Nanoparticles of various materials, such as Ag,
Au, PbS and fullerene, have previously been produced using
the evaporation/condensation technique (Gurav et al., 1994;
Kruis et al., 2000; Magnusson et al., 1999; Schmidt-Ott, 1988).