Abstract
In recent years, gold (Au) nanoparticles have been synthesized by means of various methods and have received promising potential in optical and biomedical detection. Au nanoparticles contain some remarkable dimension-dependent optical properties due to surface plasmon resonance (SPR) in Au nanoparticles which causes strong absorption of the incident light in visible light regions. Since SPR in well-crystallized Au nanoparticles can enhance the local electromagnetic field, it is thus expected that a greater efficiency in the photoluminescence (PL), originating from oxygen deficiency centers (ODC), can be achieved in Au-implanted SiO2 matrix. In order to demonstrate the enhancement of PL, in this story, Au nanoparticles were formed in SiO2 film using ion beam synthesis and their optical and microstructural properties were also investigated as well. The results revealed that a clear absorption peak at approximately 520 nm was identified in the UV-Vis spectra and was attributed to SPR induced by Au nanoparticles in SiO2 film. The SPR of Au nanoparticles is also dependent on thermal treatment conditions, such as annealing gas, annealing temperature and annealing time. The Au nanoparticle-containing SiO2 film also displayed several distinctive peaks at approximately 310, 380, 450, and 600 nm in the PL spectra and were found to be associated with ODC-related defects and non-bridging oxygen hole centers (NBOHC) in SiO2 film. In addition, the PL peak intensities increase as annealing temperature increase, a finding contradictory to the defect recovery. The greatest PL emission was achieved when the Au-implanted SiO2 film was annealed at 1100 oC for 1 h under the nitrogen ambient. Therefore, the existence of Au nanoparticles in SiO2 film can induce SPR effects and enhance PL emission which was mainly due to defect dependent luminescence centers.