Electroless Deposition of Cuprous Oxide

It is generally well known that certain metals can be deposited on dielectric substrates at room temperature by aqueous, electroless chemistry following surface activation. Much less is known about electroless growth of oxides. One exide, namely cuprous, has been deposited on glass as an adherent thin film of good quality. It was formed on a precursory electroless silver film from a highly alkaline solution containing Cu+2, tartrate ion, and formaldehyde. Growth of cuprous oxide requires having Cu+2 highly coordinated with OH and also having the electroless silver, activating surface relatively free of its own oxide. Silver oxide, at least within our experimental conditions, seems to activate the codeposition of electroless Cu. Data are presented to confirm the identity of the Cu2O film. Competing reactions for the deposition of Cu2O and Cu are discussed in terms of hydroxide complexing and surface activation.