Eur. Phys. J. B 33, 109-114 (2003)
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

Abstract

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 Ag_xAu 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.