Diodelike behavior in glass-metal nanocomposites

Abstract

One-dimensional arrays of nanoparticles of silver and copper, respectively, have been grown within a silicate glass by an electrodeposition process. Silver-silica nanocomposites were prepared using a melt quenched glass whereas sol-gel derived glass was used for the synthesis of copper-silica nanocomposites. The metal particle diameters had values ranging from 1.5 to 20 nm. The composite structures exhibited a diodelike current-voltage characteristic in the temperature range 300 to 160 K for silver containing nanocomposites and at around 280 K for copper containing nanocomposites. The diode action is believed to be caused by the presence of metal-semiconductor nanojunctions in these glass-the typical number of such junctions being 60. The rather narrow range of temperature for diode action as observed in copper-silica nanocomposites is ascribed to the easy breakup of the metal nanoarrays because of the sol-gel derived medium of silica glass in which the metal phase was grown. The metal particles of diameter ~2 nm constituted the semiconducting phase in these nanojunctions.