The characterisation of point defects in diamond by luminescence spectroscopy

Luminescence spectroscopy is a vitally important technique for characterising the defects present in diamond. In this paper the two major methods for generating the emission photoluminescence and cathodoluminescence are considered, and the defects responsible for the most significant luminescence bands are discussed in detail. Problems with the donor acceptor pair model, conventionally used to interpret the broad blue and green emission bands in cathodoluminescence, are outlined, and the fundamental differences between photoluminescence and cathodoluminescence are presented. The paper concludes with a cathodoluminescence study of diamond grown by the combust ion flame technique. Not only does this material exhibit intrinsic edge emission, but there is evidence of bound-exciton recombination at a currently unknown donor or acceptor centre.