Effects of Surfactants on the Properties of Ordered Periodic Porous Silica Films

Authors report the effects of surfactants on the properties of ordered periodic porous SiO2 films. SiO2 films with a periodically ordered structure were synthesized on crystalline Si substrates by spin-coating an alkoxysilane solution mixed with a self-assembling template and a cationic alkyltrimethylammonium chloride (ATMACl, CH3(CH2)n-1N(CH3)3 Cl) surfactant, where n was 12, 14, or 16. The effects of surfactants on the properties of porous SiO2 films with a periodic pore structure were investigated. Both dielectric constant and refractive index decreased with the length of alkylchain in the template molecule ATMACl. The pore structure was controlled by the alkylchain length of the template molecule when the TEOS vapor treatment was applied. 6 refs.