Thermoelectric and Elastic Properties of Carbon Nanotubes Irradiated with High-Energy Electrons

Abstract

Abstract—The electrical conductivity, thermo-emf, and elasticity coefficient were experimentally studied in multilayered carbon nanotubes (CNTs) exposed to room-temperature irradiation. The initial CNTs with dimensions of 18 ± 7 nm were obtained via chemical vapor deposition using propane–butane as precursor. The irradiation of CNTs was implemented on Mikrotron-ST cyclic electron accelerator at the energy of 21 MeV and electron doses of 0.3 × 10¹⁷, 0.7 ×10¹⁷, 1.1 ×10¹⁷, and 1.5 × 10¹⁷ cm^–2. The characteristics of initial and irradiated samples were measured in a dielectric cylinder. The following critical parameters of dielectric–metal transition in CNTs were established: array density (ρ₁), elastic strain of CNT (ρ_rel), maximum electrical conductivity (σ_max), and elastic strain coefficient (ε). The irradiated CNTs exhibit a decrease in thermo-emf (Seebeck coefficient (α)) by 50% or more in comparison with the initial samples, which is due to the formation of radiation defects.