Silver self aggregation in a nanodevice for enhanced Raman spectroscopy: experiments vs. simplified modeling via molecular dynamics

• Published in: Nanoscale Vol. 4; no. 7; pp. 2362 - 2371
• Main Authors: Babiaczyk, Wojtek Iwo, Bonella, Sara, Ciccotti, Giovanni, Coluccio, Maria Laura, Gentile, Francesco, Di Fabrizio, Enzo
• Format: Journal Article
• Language: English
• Published: England 07.04.2012
• Subjects: Chemical Precipitation; Crystallization; Equipment Design; Microtechnology; Models, Biological; Models, Theoretical; Molecular Dynamics Simulation; Nanostructures - chemistry; Silver - chemistry; Spectrum Analysis, Raman - instrumentation; Spectrum Analysis, Raman - methods
• ISSN: 2040-3364; 2040-3372; 2040-3372
• DOI: 10.1039/c2nr30145h

We present a study, via experiments and exploratory molecular dynamics simulations, of self aggregation in cylindrical nanostructures obtained experimentally by combining high resolution electron beam lithography with electroless silver deposition. This process is key to the fabrication of a nanolens device, where a strong surface enhancement can be exploited for Raman spectroscopy. In order to investigate the process, we introduce a simple theoretical model and compare the results of simulations with the fabricated silver nanostructures during the growth phase. Our simulations qualitatively agree with the experiments and allow a general characterization of the process at length scales smaller than those easily accessible by microscopy. We identify a geometrical parameter, the aspect ratio of the cylinder, that relates two different types of growth with different characteristics and, possibly, different Raman enhancements. Experiments and (simplified) molecular dynamics modeling are combined to characterize silver self aggregation in a nanodevice for SERS.