Authors: R. Murali, E. Walters, F. Zaman, C. Tabor, W. Huang, M. El-Sayed and J.D. Meindl
Affilation: Georgia Tech, United States
Pages: 258 - 260
Keywords: surface enhanced Raman scattering, electron beam lithography, molecule detection
Metallic nano-particle pairs in close proximity to one another display surface-enhanced raman scattering (SERS). Single-molecule detection has been predicted to be possible thanks to SERS. The SERS enhancement is due an induced localized electric field at the particle’s surface caused by a localized surface plasmon resonance (LSPR). The local field can be maximized by simultaneously increasing the curvature of the particles and bringing them into close proximity to one another (particle gaps less than the particle size) [1-2]. The field intensity has been predicted to drop exponentially as the gap size is increases, and hence study of small gaps (1-20 nm) is crucial to achieving single-molecule detection. Chemical identification of hazardous substances such as Cyanide and Anthrax is then possible on an extremely small concentration level, bordering on single molecule detection. Other studies To-date, no work has been reported in the literature on the fabrication of structures with high curvature and small gaps. This work presents the fabrication of such structures using an optimized process and uses electron-beam lithography. Sub-5 nm gaps have been demonstrated.
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