Influence of Co contents on the microstructure and SERS performance of self-formed Ag nanoparticles/Ag-Co alloy films on flexible substrates

摘要

Self-formed Ag nanoparticles/Ag-Co alloy films with various Co contents were fabricated by sputtering Ag-Co composite target. Effects of Co contents in Ag-Co films on the microstructure and SERS performance of nanoparticles/alloy films were thoroughly investigated through SEM, TEM and Raman spectrometer. Amorphous Co in Ag-Co films restricted the growth of Ag grains in the films and promoted the formation and growth of Ag nanoparticles on the film's surface. The size and number of Ag nanoparticles grown on the surface were closely related to Co contents in Ag-Co films, Ag-Co film thicknesses and annealing temperatures. Ag nanoparticles/AgCo films covered with Ag layers performed ultra-sensitive Raman signals due to forming abundant active hot spots. This flexible SERS substrate could detect 10(-12) mol/L Rhodamine 6G (R6G), which indicated that this novel type of Ag nanoparticles/Ag-Co alloy films could be used and applied as high-efficient SERS substrates.