The temperature dependence of the charge carrier density, mobility and
Seebeck coefficient of melt-grown, bulk ZnGa2O4 single crystals was measured
between 10 K and 310 K. The electrical conductivity at room temperature is
about s = 286 S/cm due to a high electron concentration of n = 3.26*10^(19)
cm^(-3), caused by unintenional doping. The mobility at room temperature is mu
= 55 cm^2/Vs, whereas the scattering on ionized impurities limits the mobility
to mu =62 cm^2/Vs for temperatures lower than 180 K. The Seebeck coefficient
relative to aluminum at room temperature is S_(ZnGa2O4-Al) = (-125+-2) muV/K
and shows a temperature dependence as expected for degenerate semiconductors.
At low temperatures, around 60 K we observed a maximum of the Seebeck
coefficient due to the phonon drag effect
