Preparation of Nanoscale Ag Semishell Array with Tunable Interparticle Distance and Its Application in Surface-Enhanced Raman Scattering

Nanoscale Ag semishell arrays with controlled size and tunable interparticle distance were prepared by combining nanosphere lithography with reactive ion etching. First, a large-area ordered monolayer of polystyrene (PS) nanospheres was deposited oil glass substrates using the Langmuir-Blodgett (LB) technique. The PS spheres with different diameters were employed in LB procedures. Second, the monolayers of PS spheres were etched to control the diameter and tune the interparticle distance. Finally, a Ag layer was evaporated oil the etched PS templates. Ag films with periodical nanostructures were obtained and can be used as surface-enhanced Raman scattering (SERS) substrates. These substrates exhibited homogeneity and good enhancement ability. SERS enhancement factor (EF) was represented oil the order of 10(4)-10(5). The correlation between nanoscale morphology and SERS activity of the Substrates was investigated. When the size of Ag-semishell was fixed, the EF Value decreased with the increase of interparitcle distance. Both local Surface plasmon mode and delocalized Surface plasmon mode contributed to the total enhancement. The controlled size, tunable interparticle distance, and large-area ordered arrays of these Substrates Suggest their promising applications as functional components in spectroscopy, immunoassay, biosensors, and biochips.