Infrared resonances of self-assembled Pb nanorods

The formation of self-assembled Pb nanorods on a vicinal Si(335)/Au surface at 305 K was monitored in situ with polarization dependent infrared spectroscopy. The rods have formed from Pb evaporated on a single domain Au-stabilized Si(335) surface under ultrahigh vacuum conditions and reached lengths of about 1 mu m. As the rods are aligned almost parallel, a large optical anisotropy of the transmitted infrared light was detected. A plasmonic antennalike resonance appeared in the spectra. Since such resonance frequencies are mainly determined by the length of the rods, the growth process was directly monitored via the shift of the resonance frequency. The estimated extinction cross section at resonance frequency indicates field enhancement similar to that observed for gold nanorods. (C) 2008 American Institute of Physics.