3D analysis of dislocation networks in GaN using weak-beam dark-field electron tomography

Jonathan Simon Barnard (1) , Joanne Helen Sharp (1) , Jenna Tong (1) , P A Midgley (1)

1 DMSM - Department of Materials Science and Metallurgy [Cambridge University]

We have developed a new method of tomographically reconstructing extended three-dimensional dislocation networks using weak-beam dark-field (WBDF) imaging in a TEM. A series of WBDF images is recorded every few degrees over a large tilt range, whilst ensuring that the dark-field reflection used for imaging maintains a constant deviation parameter. With suitable filtering of the WBDF images prior to tomographic reconstruction, the three-dimensional distribution of dislocations is reproduced with high fidelity and high spatial resolution. The success of this approach is demonstrated for heteroepitaxial Mg-doped GaN films. The fidelity of the tomographic reconstruction was found to vary depending on the dislocation line-vector and the elastic anisotropy of the material.

Mots clés: Physical Sciences

Jonathan Simon Barnard, Joanne Helen Sharp, Jenna Tong, P A Midgley. 3D analysis of dislocation networks in GaN using weak-beam dark-field electron tomography. Philosophical Magazine, 2006, 86 (29-31), pp.4901-4922. ⟨10.1080/14786430600798839⟩. ⟨hal-00513717⟩