Novel Method for Solution Growth of Thin Silica Films from Tetraethoxysilane

The controlled growth of thin films of silica by a wet-chemical method is reported. Based on the same precursors as for the sol-gel process, but under conditions that lead to the growth of silica in solution with nanometer control, the technique is, unlike the sol-gel technique, also suitable for coating features with large aspect ratios (see Figure). Of particular interest for photonics: grown layers can be doped with optically active groups.