Defect and interface studies of ZnO/MgxZn1−xO heterostructures

The defect characteristics of ZnO layers grown on thin MgxZn1−xO buffer layers with two different crystal structures of cubic and wurtzite are investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and high-resolution X-ray diffraction (HRXRD). It was found that the screw dislocation density of ZnO layers grown on MgZnO-wurtzite buffer layer are lower than ZnO layers grown on MgZnO-cubic buffer layers, while the edge dislocation density in ZnO layers grown on MgZnO-wurtzite buffer layer are slightly higher than for ZnO layers grown on MgZnO-cubic buffer layers. Dislocation loop and stacking fault were observed in ZnO/MgZnO-cubic layers.