Frequency dependence of the conductivity of amorphous germanium films between 20 Hz and 26 GHz

Conductivity measurements on amorphous Ge films in the frequency range 20 Hz–26 GHz are described. Above 100 MHz the frequency dependence of the conductivity at room temperature satisfied the power law σ∝ω^s with s=0.45-0.7. No saturation of the conductivity was observed. When the Ge films were doped with 0.1–1 at. % Sb the conductivity was frequency independent up to 26 GHz. A.c. hopping conduction seems to be compatible with the experimental results.