Ion Beam Synthesis of SERS Substrate

Surface Enhanced Raman Spectroscopy (SERS) is a powerful tool to amplify weak Raman signals by an increment of the apparent Raman cross-section of the analytes. The present work reports on ion beam synthesized SERS substrates. Thin films of Au were deposited on quartz substrate using ion beam sputtering. The films were further irradiated by 1.36 MeV Xe ions to a fluence of 10
¹⁵
and 10
¹⁶
ion/cm
²
. Rutherford Backscattering (RBS) was performed for Au thin film deposited on quartz to evaluate the Au content. Thickness of the film was found to be -- 7.8nm by RBS. The FESEM was performed for pristine and irradiated samples which revealed the formation of separated distinguishable Au nanoparticles in irradiated samples. The UV-Visible spectroscopy was carried out for pristine and irradiated materials which indicated surface plasmon resonance due to the formation of Au nanoparticles after ion irradiation. The assessment of SERS was performed on High Resolution Raman using 10
⁻⁴
M di-nitro salicylic acid (DNSA) as a model analyte, which has a similar chemical structure to the commonly found explosives. The presence of NO
2
group and aromatic ring stretching vibration were observed on the irradiated sample which were otherwise not observed on the pristine sample. Hence, this demonstrated ion beam synthesis of SERS substrate.