Growth of nanoporous silicon dioxide thin films using porous alumina substrates

In this paper, we report a cost-effective and highly reproducible method for the deposition of porous SiO2 thin films by using commercially available porous alumina membranes and radio-frequency magnetron sputtering method. Due to the porous surface of the substrate and its narrow and long channels, the SiO2 thin films partially cover the pores of the alumina membranes and self-organized porous network structures are formed. The pore size depends on the thickness of the films. The morphology of the thin films consists of patterned islands which gradually coalesce together during the growth of the thin films.