Plasmon Absorption by Silver Nanoparticles on LiNbO3 Surface
The morphology and optical spectra of silver nanoparticles sputtered onto lithium niobate substrates have been studied. Silver films with small mass thicknesses (from 0.5 to 3.0 nm) are found to form oblate spheroidal (disk-like) nanoparticles on the LiNbO3 surface, with a radius of about 7 nm and a height of about 1.2 nm. The corresponding absorption spectra contain a band with a maximum at 520–640 nm, which is associated with the excitation of nanospheroid’s plasmon mode. The location of the plasmon resonance maximum is found to depend on the sign of the lithium niobate surface charge, being equal to 564 nm for the positively charged surface and to 587 nm for the negatively charged one. A mechanism for the explanation of this dependence is proposed.
Sh. Zou, G.C. Schatz. Silver nanoparticle array structures that produce giant enhancements in electromagnetic fields. Chem. Phys. Lett. 403, 62 (2005).
I. Bolesta. Surface plasmon-polaritons. Elektron. Inform. Tekhnol. 2, 3 (2012).
R.M. Navarro Yerga, M.C. Alvarez Galv’an, F. del Val-´le, J.A. Villoria de la Mano, J.L.G. Fierro. Water splitting on semiconductor catalysts under visible-light irradiation. Chem. Sus. Chem. 2, 471 (2009).
M. Hu, J. Chen, Z.Y. Li, L. Au, G.V. Hartland, X. Li, M. Marquez, Y. Xia. Gold nanostructures: engineering their plasmonic properties for biomedical applications. Chem. Soc. Rev. 35, 1084 (2006).
M.A. Garcia. Surface Plasmons in Biomedicine Recent Developments in Bio-Nanocomposites for Biomedical Applications (Nova Science, 2011).
M.A. Garcia. Surface plasmons in metallic nanoparticles: fundamentals and applications. J. Phys. D 44, 283001 (2011).
S.V. Karpov, V.S. Gerasimov, I.L. Isaev, V.A. Markel. Local anisotropy and giant enhancement of local electromagnetic fields in fractal aggregates of metal nanoparticles. Phys. Rev. B 72, 205425 (2005).
I. Bolesta, O. Kushnir, B. Kulyk, V. Gavrylyukh. Fractal structure of ultra-thin silver films. Visn. Lviv. Univ. Ser. Fiz. 47, 130 (2012).
L.B. Katsnelson, Sh.A. Furman. Method for measuring the thickness of thin films during their fabrication. Author's certificate 216961 USSR (published April 26, 1968) (in Russian).
L. Shafarenko, M. Petrou, J. Kittler. Automatic watershed segmentation of randomly textured color images. IEEE Trans. Image Process. 6, 1530 (1997) .
M. Cesaria, A.P. Caricato, M. Martino. Realistic absorption coefficient of ultrathin films. J. Opt. 14, 105701 (2012).
I.M. Bolesta, A.V. Borodchuk, A.A. Kushnir, I.I. Kolych, I.I. Syworotka. Morphology and absorption spectra of ultra-thin films of silver. J. Phys. Stud. 15, 4703 (2011).
M. Born, E. Wolf. Principles of Optics (Cambridge Univ. Press, 2000).
I.M. Bolesta, O.O. Kushnir. AFM microscopy and optical studies for the shape of particles in ultrathin silver films. Ukr. J. Phys. Opt. 13, 165 (2012).
V.V. Klimov. Nanoplasmonics (Fizmatlit, 2010) (in Russian).
S.A. Maier. Plasmonics: Fundamentals and Applications (Springer, 2007).
N. Metropolis, S. Ulam. The Monte Carlo method. J. Am. Stat. Assoc. 44, 335 (1949).
G. Mie. Beitr¨age zur Optik tr¨uber Medien, speziell kolloidaler Metall¨osungen. Ann. Phys. 330, 377 (1908).