Properties of Germanium Doped with Iron. I. Electrical Conductivity

Measurements of the temperature dependence of electrical resistivity in $p$- and $n$-type iron-doped germanium crystals indicate that Fe introduces impurity levels in Ge at 0.34±0.02 ev from the valence band and 0.27±0.02 ev from the conduction band. Such samples show very high resistivity at 77°K. At this temperature, $n$-type samples also show high photosensitivity and slow photoresponse, presumably because of hole traps.