Production of nanopowders from physical vapor deposited films on nonmetallic substrates by conjunctional freezing-assisted ultrasonic extraction method

A new technique to extract nanoscale powders from thin films deposited by a physical vapor deposition method on nonmetallic substrates is proposed. Powders were extracted from films of different materials, such as silicon, nickel, copper, iron, aluminum and cobalt, and compounds, such as aluminum nitride, aluminum oxide, copper oxide, iron oxide, nickel cobaltite, nickel ferrite, nickel oxide, silicon carbide, silicon nitride and silicon oxide. These thin films were deposited on glass substrates by magnetron sputtering, pulsed-laser deposition, spray pyrolysis or thermal evaporation, and the particle sizes of the extracted powders were comparable to those of film samples. This technique is fast, low cost, reliable, highly clean and appropriate for large-scale samples.