Specifically, it is desirable for a TCO to possess high electron mobility in order to maximise conductivity. Figure shows the experimental electron mobility of undoped and Ga-doped ZnSb 2 O 6 single crystals over the temperature range 200 K to 350 K, where we observed an impressive room temperature mobility of 49 cm 2 V -1 s -1 at the maximum doping level (2.4 × 10 20 cm -3 ), resulting in a conductivity of 1890 S cm -1 . Our THz domain spectroscopy (TDS) results on powder samples of Ga-doped ZnSb 2 O 6 also demonstrate metallic-like conductivity over a range of nominal Ga-doping percentages, peaking at around 8% Ga (grey stars in Figure ). Our single crystals display competitive electronic properties, with electron mobilities of 40 cm 2 V -1 s -1 to 60 cm 2 V -1 s -1 and conductivity on the order of 1 × 10 4 S cm -1 being common in thin films of ITO, FTO and AZO. To further understand the origin of the high mobility in ZnSb 2 O 6 , we performed charge transport calculations using the amset package. This allowed us to calculate the limits to intrinsic mobility from various scattering mechanisms including polar optical phonons (POP), acoustic deformation potentials (ADP), and ionised impurities (IMP). We found that at low carrier concentrations, corresponding to the nominally undoped sample, polar optical phonon scattering dominates, while at higher concentrations the limiting scattering mechanism switches to ionised impurity scattering. This is demonstrated in Figure , where the mobility of the undoped sample displays the strong temperature dependence typically associated with a system dominated by POP scattering, while at high carrier concentrations the mobility becomes largely temperature independent, indicative of IMP based scattering. We note that in ZnSb 2 O 6 , ADP scattering is largely unimportant, remaining unchanged and at a significantly lower rate than the other mechanisms regardless of temperature and carrier concentration. In Figure , we explicitly plot the scattering rates at room temperature and high carrier concentration, clearly showing ionised impurity scattering as the dominant scattering mechanism.