Properties of Germanium Doped with Nickel

The temperature dependence of electrical resistivity in $p$- and $n$-type nickel-doped germanium crystals indicates that nickel introduces two acceptor levels in germanium at 0.22±0.01 ev from the valence band and 0.30±0.02 ev from the conduction band. Ionization energies deduced from infrared photoconductivity studies at 77°K are in agreement with the values obtained from resistivity measurements. $N$-type samples show higher photosensitivity than $p$-type samples and demonstrate quenching effects. The distribution coefficient for nickel in germanium is about 2.3×${10}^{-6\mathrm{}}$.