Highly spatially resolved electron energy loss spectroscopy of extended defects in chemical vapor deposited diamond was performed. Analysis of the low-energy loss regime showed that the joint density of states in the vicinity of dislocation nodes and secondary stacking faults, formed by incomplete dissociation of partial dislocations, could be different to that in perfect bulk material. Extra intensity in the joint density of states below the conduction band edge and in the lower conduction band was observed, with the most marked increase at around 6eV. This was an indicator of sp2-bond character. Spatially these states were too widely dispersed to be innate to the dislocation cores, and they were thought to arise from point defect segregation to extended defects. Kramers-Kronig and valence band plasmon analysis suggested an increase in the effective electron density and mass at the dislocation nodes.

Joint Density of States at Extended Defects in CVD Diamond, Observed via Highly Spatially Resolved Electron Energy Loss Spectroscopy. U.Bangert, A.J.Harvey, M.Schreck, F.Hoermann: Physica Status Solidi A, 2005, 202[11], 2188-93