The drift mobility of holes in $n$-type germanium and electrons in $p$-type germanium has been measured as functions of impurity concentration and temperature. In single crystals of resistivity greater than 10 ohm-centimeter, the mobility at 300°K of holes is ${\mu }_P=1900\mathrm{}\pm 50$ ${\mathrm{cm}}^2$/volt-sec and of electrons is ${\mu }_N=3900\mathrm{}\pm 100$ ${\mathrm{cm}}^2$/volt-sec. For this high resistivity material, the temperature dependence of mobility in the same units is ${\mu }_P=3.5\mathrm{}\times {10}^7{T}^{-1.6\mathrm{}}$ and ${\mu }_N=9.1\mathrm{}\times {10}^8{T}^{-2.3\mathrm{}}$, in agreement with conductivity-mobility measurements.

• Received 24 July 1953

DOI:https://doi.org/10.1103/PhysRev.92.681