ELECTRON IRRADIATION OF AN UNDOPED HOMOEPITAXIAL DIAMOND TO SUPPRESS HOLE CONDUCTIVITY

The use of undoped single-crystal diamond as material for the manufacture of detectors for high-energy particles and various types of ionizing radiation is limited by background conductivity caused by boron impurities, leading to high dark currents in such metal-semiconductor-metal or metal-dielectric-metal structures. This study explores the possibility of reducing background conductivity in undoped homoepitaxial diamond through irradiation with low doses of high-energy electrons (3,5 MeV). We studied single-crystal diamonds with impurity concentrations below 1014 cm-3 nevertheless demonstrating resistivity of ~5 kΩ∙cm at room temperature. The samples were irradiated with electron doses of ~2∙1015 cm-2 and ~1016 cm-2. The results were monitored by analyzing the temperature dependence of the material's electrophysical properties and the current-voltage characteristics of detector samples made from it. The obtained results show that irradiation effectively reduces diamond conductivity by several orders of magnitude. Studies of the temperature dependences of electrophysical parameters confirm the material's stability after irradiation in the temperature range up to 1000 K, enabling the fabrication of ohmic contacts in detector structures without degradation of their characteristics. Measurements of current-voltage characteristics demonstrate a significant reduction in the dark current of a detector after irradiation. Moreover, the dark current of the irradiated samples with ohmic contacts, which exhibit enhanced mechanical and thermal stability, is comparable to that of non-irradiated samples with Schottky contacts. The obtained data open prospects for developing homoepitaxial diamond-based detectors resistant to extreme operating conditions. For citation: Timoshenko V.O., Prikhodko D.D., Tarelkin S.A., Zholudev S.I., Luparev N.V., Kornilov N.V. Electron irradiation of an undoped homoepitaxial diamond to suppress hole conductivity. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 9. P. 53-59. DOI: 10.6060/ivkkt.20256809.12y.