Chemical vapor reactions of ZnO growth by metal-organic vapor phase epitaxy

Chemical vapor reactions during ZnO growth by metal-organic vapor phase epitaxy is investigated by in-situ   monitoring using Fourier transform infrared spectroscopy. For ZnO growth, we used diethylzinc (Zn(C2H5)2Zn(C2H5)2; DEZn) and nitrous oxide (N2ON2O) as zinc and oxygen sources, respectively. With the temperature increases, N2ON2O gradually dissociates into N2N2 and O. On the other hand, ethylene (C2H4C2H4) is eliminated from DEZn by the ββ-hydride elimination process over about 300∘C. Under flowing both DEZn and N2ON2O gases, DEZn firstly reacts with O generated by N2ON2O dissociation into diethoxylzinc (Zn(OC2H5)2Zn(OC2H5)2; DEOZn), then DEOZn dissolves by elimination of C2H4C2H4. Due to these chemical vapor reactions, dihydroxyzinc (Zn(OH)2Zn(OH)2) is generated from DEZn and N2ON2O, and changes into ZnO on the substrate.