Interfacial conduction in silica gels containing nanocrystalline copper oxide

Nanometer-sized copper particles have been grown within a gel derived glass in the system 60 CuO, 40 SiO2 (mole %). By heat treatment at temperatures in the range of 450-850 degrees C, copper oxide shells of thickness varying from 1.1 to 1.7 nm have been produced. DC resistivity measurements carried out over the temperature range of 30-300 degrees C show a drastically redu ced activation energy as compared to that of a reference sample with the ab ove composition. This is ascribed to the presence of an interfacial amorpho us phase generated by the assembly of nanosized copper oxide particles. (C) 2000 American Institute of Physics. [S0003-6951(00)04210-8].