Metal-to-insulator transition in silver nanolayers grown on silver oxide nanoparticlesK. 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 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.
81.07.-b - Nanoscale materials and structures: fabrication and characterization.
71.30.+h - Metal-insulator transitions and other electronic transitions.
© EDP Sciences 2004