Surface plasmons on Ag clusters induced via ultrasonic and thermal treatments and the enhancement of Si nanocrystal light emission

Quartz substrates are ultrasonically irradiated within AgNO3 solution, followed by postannealing in nitrogen atmosphere at elevated temperatures (T-a's) between 200 and 800 degrees C. Ag clusters with sizes in the order of 10(2) nm appear on the SiO2 surfaces after the ultrasonic and thermal treatments. Absorption spectra induced by localized surface plasmons (LSPs) on Ag clusters are observed. The most prominent absorption occurs for T-a=400 degrees C. From T-a=200 to 400 degrees C, AgNO3 on SiO2 experiences thermal decomposition, Ag cluster formation and ripening. From T-a=600 to 800 degrees C, Ag oxide nano-rings form. Application of the LSPs to Si nanocrystal-doped SiO2 (Si-NC:SiO2) thin film yields an enhancement of photoluminescence (PL) of Si-NCs, with a maximal 3.6-fold enhancement obtained for T-a=400 degrees C. The PL enhancement is attributed to the LSP field coupling to the exciton dipole moment of Si-NC. (C) 2014 Elsevier B.V. All rights reserved.