We fabricated ZnO thin-film transistors by rf magnetron sputtering on Si substrates held near room temperature. The best devices had field-effect mobility of more than 2 cm2/V s and an on/off ratio>10(6). These ZnO films had resistivity similar to10(5) ohm cm, with high optical transparency (>80% for wavelength >400 nm), and compressive stress <0.5 GPa. The combination of transparency in the visible, excellent transistor characteristics, and low-temperature processing makes ZnO thin-film transistors attractive for flexible electronics on temperature sensitive substrates. (C) 2003 American Institute of Physics.