High-resolution electron microscopy of stacking faults in heteroepitaxial ZnO/LiTaO₃

The structural analyses of the defects for ZnO films on (011̄2) r-plane LiTaO₃ substrate were carried out using electron diffraction, high-resolution electron microscopy (HREM), and image simulations. The epitaxial relationship was found to be [0001]_ZnO|[01̄11]_LiTaO3 and (112̄0)_ZnO||(011̄2)_LiTaO3. The dominant defects observed in the ZnO films were characterized as the type I₁ intrinsic stacking faults with the displacement vector (a/6)[202̄3], leading to a local zinc-blende structure in the wurtzite ZnO matrix. HREM studies show that stacking faults in the ZnO film may be formed to accommodate tilting of the films as required to maintain a particular epitaxial relationship with respect to the substrate.