Some Properties of High ResistivityP-Type Germanium

A summary is given of some characteristics of single crystals of high resistivity, homogeneous, $P$-type germanium. The Hall effect, resistivity, and rectification characteristics of this material were studied with respect to changes of temperature and magnetic field. A very high mobility figure at 25°C (∼2730 ${\mathrm{cm}}^2$/volt-sec. for a field of 3600 gauss) was obtained by calculating $\frac{{10}^{8}R}{\rho }$. An effect of type of contact at the Hall probes on Hall effect measurements is pointed out. The resistivity of the material was 18.8 ohm-cm average, the Hall coefficient 5.14×${10}^{-4\mathrm{}}$ volt-cm/amp.-gauss. The magneto-resistance of this germanium amounted to about 22 percent in a field of 13,750 gauss. The Hall coefficient decreased by about 22 percent between 3600 and 13,750 gauss. The band separation for one sample was 0.82 volts from Hall effect data, 0.75 from the resistivity. The mobility was found to obey a $T^{-2.0\mathrm{}}$ law in the temperature range 78 to 400°K. This $P$-type material exhibited only slight rectification.