Interdigitated silver nanoelectrode arrays: a surface-enhanced Raman scattering platform for monitoring the reorientation of molecules under an external electric field

In this paper, we propose a type of interdigitated silver nanoelectrode array fabricated by electron-beam lithography and ion beam etching. Ag nanoelectrode arrays with a width of 90 nm and a period of 150 nm have been successfully fabricated over a large area of 100  ×  100 µm². The Ag interdigitated nanoelectrode arrays have been employed in surface-enhanced Raman scattering (SERS) measurements under different oscillating electric fields, in which the SERS signal of p-thiocresol (C₇H₈S) of 10⁻⁶ M was easily detected. Moreover, the intensity of the Raman modes exhibited distinguishable variations while changing the strengths and frequencies of electric field, which could be attributed to the field-induced stretching and distortion mechanics of molecular bonds. These results demonstrated that the Ag interdigitated nanoelectrode arrays would be a good candidate for sensing devices in the area of analytes detection, by taking advantage of the ability to modulate the orientation of molecules. (paper)