ИСТИНА

Comparative study of photoluminescence (PL) and cathodo-luminescence (CL) is performed for the needle-like diamond crystallites. The individual diamond crystallites with lengths of 100 to 160 µm and transverse dimensions up to about 10 µm were obtained by selective oxidation of polycrystalline films produced by chemical vapor deposition (CVD) from hydrogen-methane gas mixture activated by a direct current (DC) discharge. The diamond films and crystallites were obtained also with addition of gaseous nitrogen during CVD growth. The samples of the needle-like diamonds of these two types (obtained with and without nitrogen addition) were studied to obtain PL and CL spectra and spatial distribution of the luminescence intensity at various wavelengths. Spectral characteristics of PL and CL indicate presence of luminescence centers related to nitrogen and silicon in diamond structure. While detected space distribution of the luminescence intensity is assumed to be connected with structural performance of the crystallites, its dependence on excitation by photons and electrons is assumed to be evidence of charge state variation of corresponding luminescent centers.