Transmission X-ray topography (X-ray imaging) was used to characterize the density and type of the native dislocations in ZnO substrates. C-oriented ZnO bulk materials from different origins were compared, either high purity chemical vapor transport grown or commercial, hydrothermally grown wafers. Elongated dislocations lying within the substrate were found in hydrothermal substrates. In chemical vapor transport crystals, the density of dislocations was found to be too high for X-ray determination of their Burgers vector. However, in hydrothermal crystals, the density of dislocations was found to be in the range < 104/cm2 and extend mainly within the substrate. Whereas complete Burgers vector identification was not achieved, two types of dislocation were revealed: grown-in, swirled dislocations ("high" temperature) and linear, gliding dislocations; which most probably developed during the cooling steps in (01•0) glide planes.

Characterisation of Dislocations in ZnO by X-ray Imaging. Burle, N., Baudin, F., Jonchere, A., Gergaud, P., Feuillet, G.: Journal of Physics: Conference Series, 2011, 281[1], 012004