Effects of Ion Energy Control on Production of Nitrogen–C₆₀ Compounds by Ion Implantation

Abstract

Nitrogen–C60 compounds such as azafullerene (C59N) and nitrogen-atom-encapsulated fullerene (N@C60) are produced by implanting nitrogen ions into C60 thin films on a substrate immersed in an electron cyclotron resonance plasma under a mirror magnetic field. Each compound is found to be synthesized, depending on the ion energy provided by the potential difference between the substrate and the plasma. The optimum energy for C59N synthesis is approximately 40–50 eV, and the amount of C59N decreases in an ion energy range larger than 50 eV. In contrast, an ion energy larger than 20 eV is required for N@C60 synthesis.

Effects of plasma parameters on increasing the purity of nitrogen atom encapsulated fullerene in an RF plasma

“…3 is due to the hyperfine interaction with 14 N nucleus (I = 1) and also for the electron spin of S = 3/2 [6] as discussed in the preceding section. By following previous reports [12,16], we have calculated the concentration of N@C 60 by comparing both of the integrated shaded areas of tempol and sample ( Fig. 3) with each other.…”

“…N@C 60 has been synthesized by ion implantation [5], glow discharge [6,10], and radio frequency discharge [11] methods so far, and it had been reported that the irradiation of nitrogen atom ions to C 60 is necessary for the efficient synthesis of N@C 60 . However, the purity which is defined as a ratio between concentration of N@C 60 and C 60 is very low (N@C 60 /C 60 = 10 −3 % to 10 −2 %) at present [12,13]. Although the purity can be improved by high performance liquid chromatography (HPLC) [14].…”

Electrical Transport Properties of C59N Azafullerene Encapsulated Double-Walled Carbon Nanotube

“…The azafullerene C 59 N was synthesized by a nitrogen plasma irradiation method [8]. A plasma was produced by applying an RF power with a frequency of 13.56 MHz, and nitrogen ions in the plasma were generated and accelerated toward a substrate by a sheath electric field in front of the deposited C 60 fullerene.…”

Development of low-energy and high-current-density ion beam system

“…An energy of approximately 100 V is favorable for producing specific materials such as diamond and fullerenes encapsulating a particle. 1,2 However, the components of low-energy ion beams diverge soon after their extraction by a grounded electrode owing to the self-electric field of ions. Therefore, technologies to suppress the beam divergence are required.…”