Surface Enhanced Raman Scattering of Silver Nanopartcles Formed from Silver Oxide Films with Different Composition Ratios

Abstract

We report that the composition ratio of a silver oxide film affects the intensity of surface-enhanced raman scattering (SERS) from a film on which a focused laser beam is incident. Three different composition films (AgxO) of x=1.1, 1.7, and 2.4 were fabricated by rf reactive magnetron sputtering with a silver target using a gas mixture of Ar and O2. The composition of the silver oxide films was controlled by varying the gas mixture ratio during sputtering. A He–Ne laser beam was focused on a AgxO film dipped in a solution of benzoic acid diluted with 2-propanol. It was found that the Ag2.4O film generated SERS and formed silver nanoparticles at the lowest laser power of irradiation. For an Ag1.1O film, although the laser power required the generation of SERS and formation of silver nanoparticles was highest, the film generated the strongest SERS signal at a higher laser power of irradiation since the film could form silver nanoparticles without the formation of a silver-film-like structure such as that observed in the Ag1.7O and Ag2.4O films.