Electrochemical 3D-growth of amorphous silica gel

The electrochemically assisted sol-gel deposition of silica (EADS) is an emerging technology,which allows the deposition of a silica layer under local basic conditions using a stable acidic solution of tetraethyl orthosilicate. In this paper, the EADS process was fully characterized by cyclic voltammetry and chronoamperometry, under different conditions; i.e. precursor concentration and applied potential.Moreover, thicknesswasmeasured at different times by ellipsometry, whereas scanning electron microscopy was used to investigate the morphology. Surprisinglywe found that the potentiostatic current transient resembles that of a typical nucleation and growth galvanic deposition. This phenomenonwas explained on the basis of an increased proton availability and conductivity trough the Si–OH groups of hydrated diffused sol-gel layer.