Incorporation of sol–gel SnO2:Sb into nanoporous SiO2

Abstract

Silicon oxide films thermally grown on Si(100) wafers were irradiated with 200MeV 197Au ions in the 109–1010cm−2 fluence range. The targets were then etched at room temperature in aqueous HF solution (1vol.%) for various durations. Atomic force microscopy (AFM) in the tapping mode was used to probe the processed surfaces. Conical holes with a low size dispersion were evidenced. Their surface diameter varies between 20 and 70nm, depending on the etching time. Sol–gel dip coating technique, associated with a further annealing treatment performed at 500°C for 15min, was used to fill the nanopores created in SiO2 with a transparent conductive oxide (SnO2 doped with antimony). Transmission electron microscopy (TEM) performed on cross-sectional specimen showed that SnO2:Sb crystallites of ∼5nm mean size are trapped in the holes without degrading their geometry.