It is demonstrated that a 300-keV transmission electron microscope is a powerful tool for creating carefully controlled radiation damage in diamond specimens. Irradiations may be performed in a few minutes over areas of diameter 50μm at any chosen temperature, dose, orientation and accelerating voltage up to the limit permitted. Subsequent annealing may be performed in-situ prior to detailed investigation by low-temperature photoluminescence microscopy. The results give strong evidence of the creation of self-interstitials and of the complexes that they form with impurities or dopants in the material under study.

Chemical Vapour Deposited diamond films prepared by various methods have been studied by cathodoluminescence topography and other microscopic techniques. The 533 nm and 575 nm nitrogen-related emission bands have been studied in some detail and direct comparison is made of the results. In particular, splitting of the 575 nm system has been used to estimate the stress variation within square facets on well-formed, large, individual crystals. Tensile stresses of about 0.5GPa are found near the surface and compressive stresses of 3GPa are found at greater depths. A new system with a zero-phonon line at 713 nm is reported and its origin discussed.

Large synthetic single-crystal diamonds can be grown under conditions of high pressure and high temperature by the reconstitution technique [l], which are used in a variety of industrial applications; but they often contain defects.Crystals up to 4x4x2 mm3 in size, which had been grown in either the [001] or the [111] direction, were studied by a combination of rocking-curve analysis and x-ray topography in symmetric(+,-) Bragg-Bragg diffraction geomet1ies, using synchrotron radiation ( = 0.1 nm).By recording series of topographs in all four principal azimuths (chi= 0, 90, 180, 270), variations in relative lattice pm•ameter (delta a!aO) were distinguished from misorientations.The strains associated with various types of defect were measured: (a) in populations of small inclusions (of diameter 1-5 micron) dispersed in diamond mat1ix; (b) across growth-sector boundaries separating sectors containing different concentrations of impurities; and (c) close to relatively large (100m diameter.1 mm long) cylindrical metal inclusions with axes along <110:> directions.Rocking curves were recorded from small specimen m•eas selected by a translatable pin-hole in order to determine the extent of the strains and to calculate strain gradients.The various types of defect gave characteristic measurements for delta a/aO falling in the range 6-36 parts per million and for mismientations in the range 4-40 me seconds [2,3].