INVESTIGADORES
SCAFFARDI Lucia Beatriz
artículos
Título:
OPTICAL EXTINCTION SPECTROSCOPY USED TO CHARACTERIZE METALLIC NANOWIRES
Autor/es:
L. B. SCAFFARDI; M. LESTER; D. SKIGIN; J. O. TOCHO
Revista:
NANOTECHNOLOGY
Editorial:
IOP Institute of Physics Publishing
Referencias:
Lugar: Londres; Año: 2007 vol. 18 p. 3154021 - 3154028
ISSN:
0957-4484
Resumen:
We present a method for sizing metallic nanowires through the analysis of the extinction spectra of the scattered light when they are illuminated alternatively with p and s polarization waves. The method is applied to isolated silver nanowires in air or immersed in index matching oil. The dielectric function of silver is affected by the size of the cylinders, and its influence on the extinction spectra near the plasmon resonance or near the dip position was considered. Due to the size of the nanocylinders, it is necessary to use two different permittivities to analyze the behaviour of the material under different polarization incidences. This introduces anisotropy in the system, which comprises isotropic cylinders. The behaviour of the extinction spectra for p waves allow us to determine the wire radii, taking into account the plasmon peak position for radii larger than 7 nm, or alternatively, by using the contrast between maximum and minimum intensity near the plasmon frequency, for radii lower than 5 nm. For s waves, although no plasmon peak appears, we can determine the radii analyzing the contrast between the ridge of the spectra near 260 - 275 nm and the dip near 320 ? 330 nm for radii larger than 10 nm, or analyzing the slope in the spectra over 350 nm, for radii below 10 nm. Spectral extinction is a very useful, simple and inexpensive alternative technique to characterize the radius of nanocylinders when the electronic microscopy (TEM or SEM) is not available.