https://doi.org/10.1140/epjb/e2003-00147-x
Effect of interfacial alloying on the surface plasmon resonance of nanocrystalline Au-Ag multilayer thin films
1
Department of Materials Science, Indian Association for the Cultivation of Science,
Calcutta-700 032, India
2
Inter University Consortium for DAE Facilities, Sector-III, Block- LB/8, Bidhan Nagar,
Calcutta-700 098, India
Corresponding author: a msakp@mahendra.iacs.res.in
Received:
17
October
2002
Revised:
26
February
2003
Published online:
23
May
2003
Nanocrystalline Au and Ag in multilayer thin film form with Au/Ag/Au structure
were prepared by high pressure (~40 Pa) d.c. sputtering techniques. The Ag
concentrations in AgxAu films were changed from x = 0 to 1. These multilayer films
with varying Ag concentration showed significant changes in microstructures obtained
from TEM and XRD analyses. The optical absorption spectra of these multilayer films
showed a single plasmon band confirming the formation of Au-Ag alloy. We ascribe this
alloying to the interfacial reactions in nanophase limited at the Au-Ag interface. The red-shift and broadening of the plasmon bands with the increase in silver concentration could
be associated to the increase in size of the nanoparticles and its distribution. The observed
red shift in the plasmon band may be associated with the change in electronic structure at
the Au-Ag interface due to configuration mixing of the atomic energy levels of Au and Ag.
PACS: 78.67.Pt – Multilayers; superlattices / 78.66.Bz – Metals and metallic alloys / 78.67.Bf – Nanocrystals and nanoparticles
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003