Electron-energy-loss spectra recorded from very small volumes of diamond containing individual dislocations show extra intensity within the band gap just below the 1s–to–conduction-band threshold energy, when compared to spectra recorded from neighboring defect-free regions. This is interpreted as direct evidence for the presence of vacant defect states associated with the dislocation structure. The contribution of the ${\pi }^{\mathrm{*}}$ states from the surface layers to this region of the spectra is completely removed by calculating the difference between the spectra recorded on and off the defect.

• Received 5 June 1989

DOI:https://doi.org/10.1103/PhysRevB.40.9888