Controlled structural and optical properties of nanostructured Ag films reshaped by brief iodization

Reshaping of silver thin film microstructural features was achieved by brief iodization for creating surface-enhanced Raman scattering substrate pristine Ag thin films (~ 30 nm thick) fabricated by thermal evaporation which were iodized for ≤ 10 min at 300 K. As-fabricated thin films are quasi-amorphous but prolonged iodization makes them progressively more crystalline. X-ray diffraction pattern showed an fcc structure (single phase) with high crystallinity. Field emission scanning electron micrograph results show that the size of reshaped silver nanoparticles was found to be ~ 55 nm. UV–visible spectroscopy reveals a progressively strong absorption at 420 nm attributed to silver surface plasmon resonance of reshaped Ag nanoparticles.

► Brief exposure to I2 vapors of Ag thin films for surface modification.
► Surface plasmon resonance maximum observed with respect to time of iodization.
► Brief iodization modifier widely applicable for sensor and plasmonic technologies.