FEATURES OF THE TECHNOLOGY OF HOMOEPITAXIAL CHEMICAL DEPOSITION OF THIN DIAMOND LAYERS ON A NITROGEN-DOPED SINGLE-CRYSTAL DIAMOND SUBSTRATE

In this paper, we study the formation and properties of diamond structures designed to convert the beta decay energy of the radioactive isotope 63Ni into electrical energy. Diamond substrates with different nitrogen concentrations (300 ppm and 60 ppm) were grown using the temperature gradient high-pressure thermonuclear technique (TG-HPHT). Analysis showed that a high nitrogen content leads to a significant increase in the number of structural defects in the substrates. Homoepitaxial layers with a low impurity content were synthesized using chemical vapor deposition on the diamond substrates. Then n-type Schottky diodes were manufactured by metal contacts deposition. The electrical properties of the diodes were studied when exposed to beta radiation. It was shown that substrates with a high nitrogen concentration inherit structural defects, which lead to high leakage currents and make such substrates unsuitable for creating efficient energy converters. At the same time, substrates with a nitrogen concentration of 60 ppm provide low leakage current and efficient energy conversion at temperatures up to 500 °C. The maximum electrical power was 170 pW with an efficiency of about 1%. The results demonstrate the importance of optimizing the nitrogen doping level and the crystalline quality of the substrates for creating efficient and durable radioisotope energy converters. For citation: Tarelkin S.A., Kornilov N.V., Kuznetsov M.S., Luparev N.V., Martyushov S.Yu., Timoshenko V.O. Features of the technology of homoepitaxial chemical deposition of thin diamond layers on a nitrogen-doped single-crystal diamond substrate. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 9. P. 60-65. DOI: 10.6060/ivkkt.20256809.11y.