Gold nanocomposites

A series of nanocomposites, finely divided gold dispersions in solid ceramic matrices, were generated by reactive sputtering of gold alloys in a nitrogen plasma. Gold alloys examined were different compositions of Au–Ga, Au–Al, and Au–Si. The average size of the gold particles was in the range of 3–8 nm. These nanocomposites show interesting chemical characteristics as well as optoelectronic properties. The gold/gallium nitride composite is particularly interesting since GaN is a wide band semiconductor. The gallium nitride composite is also interesting because upon heating at 800 °C the material releases nitrogen and produces a gold–gallium alloy. This property was exploited to generate microscopic metal lines by maskless laser writing and its use explored for brazing ceramic and metal components. The resistivity of the Au/GaN nanocomposite films varied several orders of magnitude depending on the gold loading.