Charge carrier density, mobility and Seebeck coefficient of melt-grown bulk ZnGa2O4 single crystals
Abstract
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 cm2/Vs, whereas the scattering on ionized impurities limits the mobility to mu =62 cm2/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.