Morphology and surface-plasmon resonance of silver nanoparticles sandwiched between Si{sub 3}N{sub 4} and BN layers
- Laboratoire de Metallurgie Physique, Unite Mixte de Recherche (UMR), Centre National de la Recherche Scientifique CNRS 6630--Universite de Poitiers, SP2MI, Boulevard M. et P. Curie, 86962 Futuroscope Chasseneuil Cedex (France)
Nanocermet trilayered thin films consisting of silver nanoclusters sandwiched between two dielectric layers (the buffer and the cap) have been synthesized by ion-beam sputtering with an alternate deposition of the metal and the dielectric species. The influence of the amount of silver, the nature of the buffer and the cap (BN or Si{sub 3}N{sub 4}), and a time delay before the cap deposition on clusters morphology and repartition have been investigated by transmission electron microscopy. It has been observed that the clusters display truncated ellipsoidal shapes in which the height to diameter ratio H/D decreases as the amount of deposited silver increases. For a given amount of silver, this ratio is lower in the case of a Si{sub 3}N{sub 4} cap, whatever the nature of the buffer. Two explanations are proposed to account for this 'cap effect' on clusters morphology: the first one is based on a calculation of the H/D minimizing the surface free energy of the clusters embedded between the buffer and the cap; the second one holds on the shape relaxation of the coalesced nonequilibrium clusters towards their equilibrium shape with the buffer, this process occurring until clusters are fully covered with the cap. Because of the higher deposition rate of Si{sub 3}N{sub 4} compared to BN, a Si{sub 3}N{sub 4} cap would allow a less efficient reshaping and consequently lead to flatter clusters. This explanation is supported by the temporal evolution of clusters morphology and repartition observed during the time delay before deposition of the cap. The evolution of the spectral position of the surface-plasmon resonance (SPR) of the trilayers as a function of their structure has also been investigated by optical transmittance measurements. The influence of cluster morphology, as well as the nature of the buffer and the cap on the SPR spectral position are discussed.
- OSTI ID:
- 20714160
- Journal Information:
- Journal of Applied Physics, Vol. 98, Issue 11; Other Information: DOI: 10.1063/1.2139828; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pulsed laser deposition of single layer, hexagonal boron nitride (white graphene, h-BN) on fiber-oriented Ag(111)/SrTiO 3 (001)
Pulsed laser deposition of single layer, hexagonal boron nitride (white graphene, h-BN) on fiber-oriented Ag(111)/SrTiO{sub 3}(001)