Nanoprobe cathodoluminescence scanning electron microscope as applied to synthesized diamond

A specific cold stage and programmable photon counting system was developed for the nanoprobe cathodoluminescence scanning electron microscope (CLSEM) to characterize synthesized diamonds. This development has enabled the nanoprobe CLSEM to obtain luminescence spectra from synthesized diamond specimens even under irradiation of an electron beam of very low current intensity of 0.1–1 nA at specimen temperature from ∼85 K to room temperature. The dependence of the CL-spectra of the free exciton recombination emission (λ = 235.2 nm) on the specimen temperature has led to an evaluation of the physical quantity representing the crystallinity of the synthesized diamond under investigation. The cross-sectional transmission electron microscopic observation has also revealed that the sample is almost free from observable crystal defects, i.e. dislocations, stacking faults etc., which are quite often observed in synthesized diamonds under transmission election microscopy.