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Title: Growth of Au nanoparticle films and the effect of nanoparticle shape on plasmon peak wavelength

Metal nanoparticles (NPs) exhibit localized surface plasmon resonance (LSPR) and thus have potential for use in a wide range of applications. A facile technique for the preparation of NP films using an electron-cyclotron-resonance plasma sputtering method without a dewetting process is described. Field emission scanning electron microscopy (FE-SEM) observations revealed that the Au NPs grew independently as island-like particles during the first stage of sputtering and then coalesced with one another as sputtering time increased to ultimately form a continuous film. A plasmon absorption peak was observed via optical measurement of absorption efficiency. The LSPR peak shifted toward longer wavelengths (red shift) with an increase in sputtering time. The cause of this plasmon peak shift was theoretically investigated using the finite-difference time-domain calculation method. A realistic statistical distribution of the particle shapes based on FE-SEM observations was applied for the analysis, which has not been previously reported. It was determined that the change in the shape of the NPs from spheroidal to oval or slender due to coalescence with neighbouring NPs caused the LSPR peak shift. These results may enable the design of LSPR devices by controlling the characteristics of the nanoparticles, such as their size, shape, number density, andmore » coverage.« less
Authors:
; ;  [1] ;  [2]
  1. Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo Bunkyo, Tokyo 113-8656 (Japan)
  2. Application and Technical Support, Elionix, Inc., 3-7-6 Motoyokoyama Hachioji, Tokyo 192-0063 (Japan)
Publication Date:
OSTI Identifier:
22275527
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ABSORPTION; CALCULATION METHODS; COALESCENCE; CRYSTAL GROWTH; ELECTRON CYCLOTRON-RESONANCE; FIELD EMISSION; GOLD; NANOSTRUCTURES; PARTICLES; PLASMA; RED SHIFT; SHAPE; SPUTTERING; THIN FILMS