The structure characteristics of ZnO thin films epitaxially deposited on two-inch (00.1) sapphire substrate by atmospheric metalorganic chemical vapor deposition (AP-MOCVD) were determined by X-ray double-crystal diffractometry methods. The strained lattice parameters

misorientation

bending radius and stress of ZnO films were estimated. The strained ZnO lattice parameters and misorientation between ZnO film and substrate were attained from a pair of symmetric and asymmetric diffraction

which contain the diffraction peaks of ZnO epilayer and sapphire substrate.The experimental bending radius was determined from the differences of the X-ray rocking curve peak positions move of the different points on ZnO film and experimental stress was calculated from that radius. Theoretical bending radius and residual thermal stress were also calculated

which is caused by the difference in the thermal expansion coefficients between the ZnO layer and sapphire substrate. The result shows that misorientation and lattice distortion were induced in ZnO layer by the actions of thermal and lattice stress. The misorientation azimuth angle is nearly the same with the miscut azimuth of sapphire substrate

which indicates that substrate miscut is one of the key factors of the misorientation

but the misoriention angle is greatly little camparing with the substrate miscut angle. Comparing to the direct-growing film

the sample with a low-temperature buffer layer has less misorientation angle and lattice stress. Meanwhile

the experimental bending radius of the sample with a low-temperature buffer layer is smaller than that of the direct-growing sample and residual thermal stress is relatively bigger. That means the low-temperature buffer layer is of great benefit to reduce the misoriention and lattice distortion of ZnO films on Al

2

O

3

and enhance the quality of ZnO film.