Abstract:ZnO thin-filmtransistors (TFTs) have attracted considerable R&D interest due to their high transparency and low photosensitivity compared with typical a-Si:H TFTs. The electrical characteristics of ZnO thinfilms may be controlled by doping with ternary element, for instance Al, Ga, In, Mg, Zr, etc. In this study, Zn1 − xMgxO (x = 0 to 0.36) thinfilms were deposited on glass substrates by spin coating. The as-depositedfilms were baked at 300 °C for 10 min and then annealed at 500 °C for 1 h in air. The results show that, addition of Mg-species in ZnO films markedly enhanced the uniformity of film thickness and improved optical properties. The Zn0.8Mg0.2O film exhibited the best transparency of 92%, an increase of ∼ 15% over a pure ZnO film, and the rms roughness value decreased to 1.63. The Zn1 − xMgxO TFTs were demonstrated to have n-type enhancement behavior. The optimum device with Zn0.8Mg0.2O channellayer had a field-effect mobility of 0.1 cm2/V s, a threshold voltage of 6.0 V, and an on/off ratio more than 107.