Probing surface plasmons in individual Ag nanoparticles in the ultra-violet spectral regime

Abstract

Previous investigations of surface plasmons in Ag largely focused on their excitations in the visible spectral regime. Using scanning transmission electron microscopy with an electron beam of 0.2 nm in conjunction with electron energy-loss spectroscopy, we spectrally and spatially probe the surface plasmons in individual Ag nanoparticles (approximately 30 nm), grown on Si, in the ultra-violet spectral regime. The nanomaterials show respective sharp and broad surface-plasmon resonances at approximately 3.5 eV (approximately 355 nm) and approximately 7.0 eV (approximately 177 nm), and the correlated spectral calculations established their multipolar characteristics. The near-field distributions of the surface plasmons on the nanoparticles were also mapped out, revealing the predominant dipolar nature of the 3.5 eV excitation with obvious near-field enhancements at one end of the nano-object. The unveiled near-field enhancements have potential applications in plasmonics and molecular sensing.

Plasmons dispersion and nonvertical interband transitions in single crystal Bi2Se3investigated by electron energy-loss spectroscopy

“…1(a) and (b)), the spectral features at ~5.5 and ~10 eV are further weaken but still visible, signifying the characteristic of the evanescent wave fields of SPs. 16,18,22,26 The STEM-EELS spectrum imaging, 27 which has been well established to probe SPs in noble metals [28][29][30] and semiconductor 31 , was performed to further confirm the physical origin of the spectral features at ~5.5 and ~10 eV as SPs. Figure 1 (c)- (e) show the STEM-EELS intensity maps, measured from the same area in HAADF image (inset, Fig.…”

Localized Plasmon in Silver Nanoparticles Synthesized by Microwave Radiation

“…A nano-metric material has dimensions under 100 nm with varied shapes like spheres, cubes, pyramids, rods, etc. This morphology, sizes and electric field intensities determine the Nps properties, each one with a characteristic plasmonic D DAVID PUBLISHING resonance [5][6][7][8]. Various methods have been implemented to synthesize NPs Ag.…”

Spectroscopic characterizations of individual single-crystalline GaN nanowires in visible/ultra-violet regime

“…: +886 2 33665295; fax: +886 2 23655404. (EELS), STEM-EELS, features a subnanometer-scale spatial resolution (determined by the electron-probe size, usually a few Å) and a wide spectroscopic range from near-infrared to soft X-ray (Chu et al, 2008(Chu et al, , 2009a(Chu et al, , 2009bLiou et al, 2009;Nelayah et al, 2007). STEM-EELS is, therefore, ideal for tackling electronic excitations in the individual NWs in the indicated visible/UV spectral regime.…”

“…In STEM-EELS, the electron probe can couple both to collective resonances, e.g., surface and volume plasmons, and single-particle excitations, e.g., interband transitions and core-level ionizations, resulting in electron energy losses (Chu et al, 2008(Chu et al, , 2009a(Chu et al, , 2009bLiou et al, 2009;Nelayah et al, 2007;Kimoto et al, 2007). A thorough characterization of energy-loss features as a function of the electron-probe position on individual nano-objects had led to exciting physics on various topics, for example, unveiling optical surface-plasmon modes in Au and Ag nanoparticles (Chu et al, 2009a(Chu et al, , 2009bNelayah et al, 2007) and UV-range surface-plasmon coupling in multi-wall carbon nanotubes (Stéphan et al, 2002).…”

“…A thorough characterization of energy-loss features as a function of the electron-probe position on individual nano-objects had led to exciting physics on various topics, for example, unveiling optical surface-plasmon modes in Au and Ag nanoparticles (Chu et al, 2009a(Chu et al, , 2009bNelayah et al, 2007) and UV-range surface-plasmon coupling in multi-wall carbon nanotubes (Stéphan et al, 2002). There have also been extensive (S)TEM-EELS studies on GaN films (Gu et al, 2007;Brockt and Lakner, 2000;Keast et al, 2002;Sánchez et al, 2004;Erni and Browning, 2008) and a recent report on individual single-crystalline NWs (Lari et al, 2008).…”