The strain reduction and quality improvement in ZnO film by a 30° in-plane rotation with respect to the Al 2O 3 substrate

Abstract

The in-plane orientation of epitaxial ZnO thin film on Al 2O 3(0 0 0 1) was determined by azimuthal scan of X-ray diffraction. Comprehensive structural characterizations, including the lattice strain in perpendicular direction, the defect density, were obtained from high resolution X-ray diffraction. It's found that a 30° rotation in ZnO against Al 2O 3, resulting in ZnO〈1 1 2 0〉//Al 2O 3〈1 0 1 0〉, can efficiently reduce the strain and defects in ZnO layer. Consequently, the optical property is significantly improved.