Alternating current electrical properties of evaporated cerium dioxide films

Abstract

Alternating current measurements are described for amorphous CeO2 thin film metal-insulator-metal samples prepared by vacuum evaporation. The behaviour of the AC conductivity σ(ω) is similar to the earlier observations for many other types of amorphous semiconductors, which obey an equation of the form σ(ω) = Aω s , ω being the radial frequency and the index s having different values at different temperatures. The conduction process involves the hopping of electrons or polarons. The Elliott (1977) model satisfactorily accounts for the frequency dependence of conductivity and the temperature dependence of s. The capacitance of the sample shows an increase with increasing temperature certainly in the lower frequency range.