Abstract
DC and transient photoconductivity measurements on UHV-evaporated amorphous germanium films show a temperature-independent component of the photocurrent. This component is independent of field, a feature contrasting with the strong field dependence of the dark current, which is due to hopping. It shows a decay faster than 5 ns and the product eta mu tau equals 1.9*10-12 cm2V-1, indicating conduction in extended states. A similar process is also found in bulk phosphorus.