Grazing Incidence X-ray Topographic Studies of Threading Dislocations in Hydrothermal Grown ZnO Single Crystal Substrates

Abstract

ABSTRACTZnO single crystal substrates grown by the hydrothermal method have been characterized by grazing incidence X-ray topography using both monochromaticand whitesynchrotron X ray beams.11$\bar 2$4 reflection wasrecorded from the (0001) wafers and the different contrast patterns produced by different threading defects were noted. To uniquely identify the Burgers vectors of these threading dislocation defects, we use raytracingsimulation to compare with observed defect contrast. Our studies showed that threading screw dislocations are not commonly observed.Most threading edge dislocationshavetheBurgers vector of1⁄3[2$\bar 1$$\bar 1$0] or1⁄3[12$\bar 2$10]and a density of 2.88×104/cm2.