Morphology evolution and SERS activity of the nanoporous Au prepared by dealloying sputtered Au-Ag film

Nanoporous Au (NPG) films possess excellent and stable surface enhanced Raman scattering (SEAS) activity. Sputtering followed by dealloying is one of the most used techniques to prepare NPG films. The morphology of the NPG can be controlled by changing the dealloying time, therefore tuning the SEAS performance of the NPG. In the present work, Au-Ag alloy film was prepared on the Si wafer with a Cr transition layer by sputtering from a Au40Ag60 target. NPG films with tailorable average pore diameter ranging from 13 nm to 52 nm were successfully prepared by changing the dealloying time. The effect of the morphology evolution on the SEAS performance of the NPG film was investigated. The dealloyed NPG film exhibits good SEAS activity with a high EF of 2.4 x 10(5). This work provides important insights into the understanding of the correlation between the dealloying time controlled morphology and the SEAS performance of the NPG films.