Polar optical phonon (POP) scattering dominates above 425 K, whereas ionised impurity (IMP) scattering, which is comparatively constant across the temperature range, contributes the most to the total scattering below 425 K. As a result of this temperature dependence the POP scattering is dominant at all the charge carrier concentrations shown in Figure . The IMP scattering rate increases up to carrier concentrations of ∼10 20 cm -3 , above which which it largely begins to plateau. Acoustic deformation potential (ADP) scattering contributes the least to the overall scattering rate and is consistently at least one order of magnitude smaller than the total scattering rate, which can be explained by the relatively low deformation potentials of 1.6 eV in the xy plane and 0.7 eV along the z directions. The scattering rates can also be examined as a function of energy. Figure shows the normalised scattering rates at n = 2.37 × 10 20 cm -3 and T = 1000 K (similar plots at 300 K and 600 K are shown in SI Figure ).