The microstructure of a-plane ZnO grown on LaAlO3 (LAO) (001) has been systematically investigated by employing X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Based on the results of XRD and TEM, only a-plane ZnO has been found to grow on LAO (001). and it consists of two types of domains perpendicular to each other The crystal orientation relationships of a-plane ZnO domains with LAO have been verified to be (0001)(ZnO)//[110](LAO) and [1 (1) over bar 00](ZnO)// [1 (1) over bar0](LAO). The domain boundaries in the a-plane ZnO are along the direction in a rotation angle of about 45 degrees from the c-axes of ZnO. The surface morphology of ZnO films in SEM exhibits domain structure in stripe-like shape The formation of two domains can be attributed to the cubic symmetry of the surface configuration of LAO (001). 0 2009 Elsevier B V All rights reserved