Optical properties of Ag nanoclusters formed by irradiation and annealing of SiO_2/SiO_2:Ag thin films

摘要

We have deposited five periodic SiO_2/SiO_2 + Ag multi-nano-layered films on fused silica substrates using physical vapor deposition technique. The co-deposited SiO_2:Ag layers were 2.7-5 nm and SiO_2 buffer layers were 1-15 nm thick. Total thickness was between 30 and 105 nm. Different concentrations of Ag, ranging from 1.5 to 50 molecular% with respect to SiO_2 were deposited to determine relevant rates of nanocluster formation and occurrence of interaction between nanoclusters. Using interferometry as well as in situ thickness monitoring, we measured the thickness of the layers. The concentration of Ag in SiO_2 was measured with Rutherford Backscattering Spectrometry (RBS). To nucleate Ag nanoclusters, 5 MeV cross plane Si ion bombardments were performed with fluence varying between 5 × 10~(14) and 1 × 10~(16) ions/cm~2 values. Optical absorption spectra were recorded in the range of 200-900 nm in orde1r to monitor the Ag nanocluster formation in the thin films. Thermal annealing treatment at different temperatures was applied as second method to form varying size of nanoclusters. The physical properties of formed super lattice were criticized for thermoelectric applications.