We predict Seebeck coefficients of |S| ≃ 300-600 µV K -1 at carrier concentrations between 10 19 -10 20 cm -3 , which are similar to the calculations in Ref. . However, the electron lifetimes in Ref. were calculated from the deformation potential, and do not account for the dominant POP scattering, so the predicted conductivity is significantly larger than in the present study. Our predictions of higher σ and PFs with n-type are also qualitatively consistent with the "reduced" values from the calculations in Ref. .