Growth of Au Nanoparticles in NiO via Short Annealing of Precursor Material Thin Film and Optimization of Plasmonics

Au-Ni-O thin films are produced by co-deposition of Au and Ni in a simple sputter coater with a base pressure of 2.5x10(-2)mbar. The as-deposited material is comprised of a mixture of tiny grains of crystalline gold, metallic hexagonal nickel and nickel oxide. Part of the material is still amorphous. Post-deposition annealing at 530 degrees C in a furnace in air leads to the formation of nanocomposite thin films of Au and NiO. The plasmonic behavior evolution was studied with annealing time between 2min and 30h in films with an initial thickness between 3 and 54nm. Films with thickness of up to 10nm show broad localized surface plasmon resonances already in the as-deposited state, due to the presence of nanograins of gold in the dielectric matrix of NiO. Plasmonic resonances become sharp and have a blue shift tendency as the annealing time increases. This plasmonic system produced via a cost-effective way may well be useful for a variety of technological applications.