Research on cracking of SiO2 nanofilms prepared by the sol-gel method

SiO2 nanofilms were prepared by a sol-gel method with TEOS as the precursor, ethanol as the solvent, and hydrochloric acid as the catalyst. The influences of H2O, EtOH, and HCl on the surface of SiO2 film were studied by a controlled variable method, and the effects of aging time, spin-coating speed, ammonia treatment, heat treatment, and substrate on the films were also determined experimentally. Crack-free SiO2 nanofilms with tens of microns thickness were repeatedly fabricated using the optimizing parameters, and the size of SiO2 nanoparticles was in the range of 100–500 nm.