We report on the fabrication and electrical characteristics of thin film transistors (TFTs) based on low Ga-doped zinc oxide (GZO). Low Ga-doped (1 wt.%) ZnO thin films deposited as an active channel by radio frequency magnetron sputtering at room temperature exhibit a high transmittance (>80%). The devices show a mobility of similar to 5.7 cm(2)/Vs at low operation voltage of <5 V and a low turn-on voltage of similar to 0.5 V with a subthreshold swing of similar to 85 mV/decade. The TFT device performance is significantly affected by vacuum-level and annealing treatments which is attributed to the chemisorption/desorption of oxygen from the surface of active channel. Low doped GZO is a type of TFT channel material that has potential for high performance, multi-functionality and easy-process. (C) 2008 Elsevier B.V. All rights reserved.