Surface plasmon resonances of Ag-Au alloy nanoparticle films grown by sequential pulsed laser deposition at different compositions and temperatures

• Published in: Journal of applied physics 2015-04, Vol.117 (13)
• Main Authors: Verma, Shweta, Rao, B. T., Detty, A. P., Ganesan, V., Phase, D. M., Rai, S. K., Bose, A., Joshi, S. C., Kukreja, L. M.
• Format: Article
• Language: English
• Subjects: ABLATION; Applied physics; Atomic beam spectroscopy; Atomic force microscopy; Atomic properties; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPARATIVE EVALUATIONS; Composition; DIELECTRIC MATERIALS; Effective medium theory; ENERGY BEAM DEPOSITION; GOLD; INTERMETALLIC COMPOUNDS; ION MICROPROBE ANALYSIS; Laser ablation; LASER RADIATION; Lasers; MASS SPECTROSCOPY; Morphology; Nanoalloys; NANOPARTICLES; NANOSCIENCE AND NANOTECHNOLOGY; PULSED IRRADIATION; Pulsed laser deposition; Pulsed lasers; Reflectometry; RESONANCE; Secondary ion mass spectroscopy; SILVER; Silver base alloys; Spectrum analysis; SUBSTRATES; Surface plasmon resonance; SURFACES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; Thickness; THIN FILMS; Tuning; X RADIATION; X ray spectra
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4916750

We studied localized surface plasmon resonances (LSPR) at different compositions, substrate temperatures, and mass thicknesses of Ag-Au alloy nanoparticle films grown by sequential pulsed laser deposition. The LSPRs were pronounced at all compositions of the films grown at high substrate temperature of about 300 °C as compared to those grown at room temperature. The alloy formation and composition of the films were determined using X-ray photoelectron and energy dispersive spectroscopy. Films' mass thickness and compositional uniformity along the thickness were determined using X-ray reflectometry and secondary ion mass spectroscopy. Atomic force microscopic analysis revealed the formation of densely packed nanoparticles of increasing size with the number of laser ablation pulses. The LSPR wavelength red shifted with increasing either Au percentage or film mass thickness and corresponding LSPR tuning was obtained in the range of 450 to 690 nm. The alloy dielectric functions obtained from three different models were compared and the optical responses of the nanoparticle films were calculated from modified Yamaguchi effective medium theory. The tuning of LSPR was found to be due to combined effect of change in intrinsic and extrinsic parameters mainly the composition, morphology, particle-particle, and particle-substrate interactions.