Abstract To realize high thermoelectric performance, it was tried to control both high electrical conductivity (σ) and low thermal conductivity (K) for the Sn-doped indium–zinc oxide films prepared by DC magnetron sputtering. The highest power factor was obtained post-annealed at 200 °C due to the highest σ. However, the highest figure of merit was obtained annealed at 500 °C. It could be attributed to both amorphous structure with low K by phonon and the highest Hall mobility. Thermoelectric and electrical properties of the film could be controlled by both heat treatment and Sn doping with high bond enthalpy.