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

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: 4 March 2004

Abstract

Silver nanometre thick layers were grown on particles of size by subjecting the latter to a heat treatment at temperatures ranging from 500 to 543. 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. 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 . The extracted values of electrical conductivity over this temperature range showed a semiconducting behaviour with an activation energy of . 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.