Morphological Development and Etching of Gold Thin Film under UV-exposure in Chlorine-based Liquids

Gold thin film is found to be soluble in chlorine-containing liquid such as 1,2-dichloroethane, NaCl, or HCl solution under illumination, especially UV shorter than 310 nm. We attribute this to the formation of gold chloride and its desorption from the surface. Atomic force microscopy study shows that the grain-like surface morphology evolves during the etch process.