We fabricated solution-processed indium zinc oxide (IZO) thin film transistors (TFTs) at annealing temperatures as low as 250 degrees C using deep UV (DUV) irradiation in water vapor medium. The DUV light decomposed the carbon compounds in the IZO films, and the hydroxyl radicals generated when water vapor reacted with ozone effectively oxidized the films. These phenomena were confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Finally, we fabricated DUV-treated IZO TFTs in water-vapor medium at 250 degrees C with a mobility of 1.2 cm(2)/Vs and an on/off current ratio of 2.66 x 10(6). (C) 2014 Elsevier B.V. All rights reserved.