Surfactant-catalyzed SiO2 thin films preparation and characterization

SiO2 thin films are in high demand for wide range of applications including microelectronics, optoelectronics, solar energy conversion, photocatalysis, and self-cleaning coatings. The performance of thin film is strongly influenced by surface properties like surface roughness, thickness, morphology, wetting behavior, and thermal stability. In these applications, the SiO2 sols were prepared using tetraethylorthosilicate as a source of SiO2 and deposited on 100 × 40 × 2 mm3 glass slide using dip-coating method for 2 min and calcined at 250 °C for 30 min. The SiO2 thin films were obtained using DTAB, SDS, and Tween 20 (Tw 20) surfactants with the thickness of 36.92, 47.15, and 52.39 nm, respectively. Surface morphology was studied with AFM and surface roughness was depicted with 0.9528, 3.6534, and 0.9294 nm. Contact angle measurements have been performed with goniometer to evaluate the wetting behavior of the film. The contact angle of 58.01°, 48.40°, and 37.88° was observed with SDS, DTAB, and Tw 20 film, respectively. The SiO2 thin films with SDS showed more surface roughness and water repelling ability when compared to DTAB and least with Tw 20.