Hot H2O jet evolved by the exothermic reaction of H-2 with O-2 on a Pt-dispersed ZnO2 catalyst was employed for gas-phase hydrolysis of dimethyl zinc to fabricate thin ZnO films. The X-ray diffraction pattern and photoluminescence spectra showed that the ZnO epilayers directly grown on a-sapphire substrate at 873 K had a defect free crystal structure close to a single crystal. The as-grown ZnO epilayers exhibited average transparency higher than 90% in the visible and infrared regions (400-2000 nm). The epilayers had high electron mobilities of 140-170 cm(2) V-1 s(-1) and low residual electron concentrations of 1.7-6 x 10(17) cm(-3) that are significantly better than those for ZnO films so far reported by conventional chemical vapor deposition and any other energy-consuming physical method such as pulse laser deposition and molecular beam epitaxy. The present method uses the chemical energy from only H-2 and O-2, which is energy-saving and ecologically friendly, while it is superior in high-quality ZnO fabrication. It is also pointed out that the method raises unlimited possibilities for a wide range of the fabrication of high-quality metal oxide epilayers, because of the availability for various volatile alkyl metals. (C) 2009 Elsevier B.V. All rights reserved.