The electron and hole mobilities were measured between 78 and 340 K. T
he method used is based on the frequency dependence of the conductance
and the capacitance of a high resistivity diode biased in high inject
ion. The method is insensitive to uncertainties regarding the ionized
dopant densities. In the temperature range from 170 to 340 K the carri
er mobilities vary as T(-a), where a=2.34+/-0.08 for electrons while f
or holes a=2.85+/-0.05. At 77.8 K the hole mobility is 14000+/-400 cm2
/V s while the electron mobility is 24000+/-800 cm2/V s.