Effect of composition on DC conductivity of co-evaporated Cu-GeO2 thin cermet films

Thin films containing 0 to 100 vol%Cu was prepared by thermal co-evaporation. The samples were 200 nm thick, deposited at 600 K at a rate of 0.8 nm/s. DC conductivity measurements were carried out using the van der Pauw four probe technique for 0 to 100 vol%Cu films in the temperature range 150 to 600 K. Samples containing ≥60 vol%Cu exhibited a ‘metallic-like’ behaviour with positive TCR whereas lower concentrations exhibited an activated conduction mechanism with negative TCR.