We have characterized dislocations in ZnO layers grown on c-sapphire (a-Ah03) by plasma-assistedmolecular-beam epitaxy (P-MBE) with and without MgO buffer layer. Zno without MgO buffer was grown three-dimensionally(3D), while ZnO with MgO buffer was grown two-dimensionally (2D). Mosaic spread (tilt and twistangles), types and density of dislocations in the layers were studied by both high-resolution X-ray diffraction (HRXRD)and transmission electron microscopy (TEM). HRXRD experiments reveal that screw dislocation densities in the ZnOlayer are 8.1 x loBcm-2 and 6.1 x 105 cm,2,for Zno with and without MgO buffer, respectively, while edge dislocationdensities are 1.1x 1010 cm,2 and 1.3 x 105 cm,2, for ZnO with and without MgO buffer, respectively. HRXRD and TEMdata showed the same result that the major dislocations in the ZnO layers are edge type dislocations running along c-axis.Therefore, HRXRD technique can be applied to characterize dislocations in ZnO layers.Keywords: ZnO, dislocations, HRXRD, TEMPACS: 81.05.Dz, 61.72.Lk, 61.72.Dd, 68.37.Lp. A.Setiawan, I. Hamidah, S. Maryanto, S. Aisyah, and T. YaoIDepartment of Mechanical Engineering and Graduate School of Science EducationIndonesia University of Education, Setiabudhi 229 Bandung 40154, Indonesia2Geological Research and Development Centre, Diponegoro 57 Bandung 40122, Indonesia3Department of Chemistry Education Indonesia University of EducationSetiabudi 229 Bandung 40154, Indonesia4Center for Interdisciplinary Research, Tohoku University Aramaki, Aoba-ku, Sendai, 980-8578, Japan
