Surface and interference co-enhanced Raman scattering from indium tin oxide nanocap arrays

Large-area indium tin oxide (ITO) nanocap arrays are fabricated on porous anodic alumina (PAA) templates to produce robust and cost-effective surface-enhanced Raman scattering (SERS) substrates. The electromagnetic enhancement mechanism is believed to be the main reason for the enhancement. The topography of the ITO nanocap arrays can be adjusted to optimize the enhancement factor by varying the anode voltage applied to the PAA templates. The optical interference in enhanced Raman scattering from the ITO nanocap arrays with different thicknesses are systematically studied and optical self-interference from the incident, scattered, and emitted light is observed to modulate the intensity and shape of the Raman signals.