NV and N₂V color centers in electroluminescence spectra of diamond

Diamond, because of its unique properties, is a promising material for optoelectronic devices based on it: LEDs and lasers. The article examines the main optically active color centers of diamond, their characteristics and methods of production, and provides a literary overview of the most common light-emitting structures based on diamond - PIN-structures. The ways of creating these structures, their advantages and disadvantages, are considered. In the practical part of the work, it is shown that substitutional nitrogen can be embedded in the diamond structure and form, for example, such color centers as NV centers or N₂V centers in two charge states. The color of the sample, the method of excitation and the intensity of luminescence, and the width of the emission spectrum depend on the method of inclusion, concentration, and charge state of the nitrogen color centers. The spectra of photoluminescence, cathodoluminescence and electroluminescence are considered using the example of two samples. The intensity of electroluminescence in both samples is noticeably lower than that of cathodoluminescence and photoluminescence. Optically active centers are determined based on the spectra. The analysis of peaks at a certain wavelength and the width of the spectrum allow us to identify and distinguish one center from another. In sample C122, nitrogen was embedded in the structure in the form of an NV center, and in sample C130 in the form of an N2V center. Since the intensity of electroluminescence directly depends on the current in the sample, Raman spectra are given to determine inhomogeneous inclusions affecting the flow of current. The analysis of Raman spectra shows the presence of non-diamond forms of carbon in samples such as carbine and graphite. The authors declare no conflicts of interests.

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