Chemical vapor reactions during ZnO growth by metal-organic vapor phase epitaxy is investigated by in-sitit monitoring using Fourier transform infrared spectroscopy. For ZnO growth, we used diethylzine (Zn(C2H5)(2); DEZn) and nitrous oxide (N2O) as zinc and oxygen sources, respectively. With the temperature increases, N2O gradually dissociates into N-2 and O. On the other hand, ethylene (C2H4) is eliminated from DEZn by the beta-hydride elimination process over about 300 degrees C. Under flowing both DEZn and N2O gases, DEZn firstly reacts with O generated by NO dissociation into diethoxylzinc (Zn(OC2H5)(2); DEOZn), then DEOZn dissolves by elimination of C2H4. Due to these chemical vapor reactions, dihydroxyzinc (Zn(OH)(2)) is generated from DEZn and N2O, and changes into ZnO on the substrate. (c) 2006 Elsevier B.V. All rights reserved.