Current transport properties of SiO2 films containing Ge nanocrystals

The electrical transport properties of SiO2 films (⩾3 μm in thickness) containing Ge nanocrystals have been studied. We found that the films exhibit T−1/2 dependence of ln(σ) under relatively low electric fields independent of the volume fraction of Ge in the films, where T and σ are the temperature and the conductivity, respectively. The observed electrical properties could be well explained by the theory developed by Šimánek [Solid State Commun. 40, 1021 (1981)] which considers the tunneling of thermally activated carriers between neighboring nanocrystals.