Surface enhanced Raman scattering improvement of gold triangular nanoprisms by a gold reflective underlayer for chemical sensing

We report on an improvement way of the SERS signal of Au triangular nanoprisms for a highly sensitive detection of chemical molecules. This improvement is obtained by a simple addition of a gold reflective layer under Au nanoprisms. Using the same Au triangular nanoprisms obtained by nanosphere lithography, we studied experimentally the thickness effect of this gold underlayer on the SERS intensity of the triangular nanoprisms. We demonstrated that this SERS intensity increased with the thickness of the gold reflective underlayer, and this is due to the increment of the Au underlayer reflectivity. Thus, we showed that the metallic reflective underlayer has an important key for SERS enhancement. Indeed, enhancement factors of 108 were found for the most important thickness of the gold underlayer.