Silver nanocluster films on ITO coated glass as novel substrates for the detection of molecules using Surface Enhanced Raman Scattering (SERS)

A novel surface enhanced Raman scattering (SERS) substrates were prepared by a nanocluster deposition system. Silver nanoclusters were deposited on the indium tin oxide (ITO) coated glass slides. These films were annealed at 300°C for two hours to obtain the required size distribution for the desirable optical properties. The surface morphology of the films was examined using filed emission scanning electron microscope (FESEM) and atomic force microscope (AFM). The surface plasmon resonance (SPR) of the pre annealed and the annealed Ag deposited ITO coated glass substrates were measured using UV-Vis spectrophotometer. The SERS studies were carried out on these substrates with Methylene Blue (MB) as a test molecule with 10⁻⁴ to 10⁻⁸ M concentrations using 514.5 nm and 632.81 nm laser excitation wavelengths. The results show that Ag nanoclusters of average particle size of ~ 150 nm act as very good SERS substrates for the detection 10⁻⁶ M of MB. Both the electromagnetic (EM) and chemical enhancement could be contributed to the SERS signal enhancement of MB molecule.