Europhys. Lett.
Volume 66, Number 4, May 2004
Page(s) 592 - 598
Section Interdisciplinary physics and related areas of science and technology
Published online 01 May 2004
Europhys. Lett., 66 (4) , pp. 592-598 (2004)
DOI: 10.1209/epl/i2003-10230-0

Metal-to-insulator transition in silver nanolayers grown on silver oxide nanoparticles

K. Chatterjee1, S. Banerjee2 and D. Chakravorty1

1  Indian Association for the Cultivation of Science - Kolkata, 700 032, India
2  Department of Physics, Calcutta University - Kolkata, 700 009, India

(Received 22 September 2003; accepted in final form 4 March 2004)

Silver nanometre thick layers were grown on $\chem{Ag_2O}$ particles of size $\sim 21$ $\un{nm}$ by subjecting the latter to a heat treatment at temperatures ranging from 500 to 543 $\un{K}$. Optical-absorption measurements on particles of core-shell structure and dispersed in ethyl alcohol were carried out over a temperature range from 290 to 340 $\un{K}$. The results were analysed using size-dependent dielectric permittivity incorporating a free-path effect. The analyses showed the existence of a metal-to-insulator transition in silver nanoshells with a thickness equal to or less than $\sim 2$ $\un{nm}$. The extracted values of electrical conductivity over this temperature range showed a semiconducting behaviour with an activation energy of $0.05\pm 0.01$ $\un{eV}$. Direct electrical resistivity measurements substantiated these results obtained from optical absorption data. The activation energies determined from both the above measurements were in satisfactory agreement.

81.07.-b - Nanoscale materials and structures: fabrication and characterization.
71.30.+h - Metal-insulator transitions and other electronic transitions.

© EDP Sciences 2004