Figure 6

SERS effects of Ag-Au hetero-nanostructure substrates with different reaction time compared with SERS effect of silver nanostructure substrate. (a) SERS spectra and Raman spectra of 4-MBA for flower-like Ag-Au hetero-nanostructure substrates and flower-like silver nanostructure substrate respectively. (b) Is the relation between enhancement factor and gold ratio in the hetero-nanostructure substrate.