Effect of annealing atmosphere on thermal evolution of Ag nanoparticles embedded in SiO2 thin surface layers

Silver nanoparticles (NPs) were synthesized in thin surface layers of SiO2 glass by 70 keV implantation of Ag ions at a fluence of 5×1016 cm-2, and were then subjected to post thermal annealing in a temperature range of 400-800℃ at different atmospheres, e.g. Ar, N2, air. The evolution of surface morphologies, optical absorption properties, as well as compositions and structures with annealing temperature in different annealing atmospheres were studied by AFM, UV-Vis spectrophotometry and GXRD. The results clearly show that uniformly distributed Ag NPs are observed in Ar ambient samples, which have high particle density and intense optical absorption at 700℃. Similar optical properties are obtained in N2 annealed samples with larger Ag NPs. In contrast, the formation and decomposition of AgO significantly reduce optical absorption of air ambient samples. Moreover, the results of Rutherford backscattering spectroscopy reveal that the evolution of Ag particles should be ascribed to different diffusion behaviors of Ag atoms with variation of annealing temperatures and atmospheres. ©, 2015, Science Press. All right reserved.