Modulation of surface-enhanced Raman spectra by depth selective excitation of embedded indium tin oxide nanoisland arrays

Embedded transparent conducting indium tin oxide (ITO) nanoisland arrays were prepared by pulsed laser deposition of ITO films on roughened Si templates and post-annealing to investigate the surface-enhanced Raman scattering activities. Considerable Raman enhancement of a rhodamine 6G probe during Ar+ laser excitation was observed and modulated by the thickness of the ITO film due to the exponentially decaying field of the localized surface plasmon polaritons at the interface. Because the Raman-enhancing functional layer is protected at the ITO/Si interface, this system is reusable and also believed to be immune to contamination and other surface activities.