The sol-gel process is a wet-chemical technique (Chemical Solution Deposition) for the fabrication of materials (typically a metal oxide) starting either from a chemical solution (sol short for solution) or colloidal particles (sol for nanoscale particle) to produce an integrated network (gel). Typical precursors are metal alkoxides and metal chlorides, which undergo hydrolysis and polycondensation reactions to form a colloid, a system composed of solid particles (size ranging from 1 nm to 1 �… (More on Sol-gel)