The dark contrast area fills
the CNF. Figure 2b shows a high-resolution image of the carbon wall around the surface area in the Sn-filled CNF. Fringes at intervals of about 0.33 nm represent the distance between the graphite layers. These fringes are not straight but meandering and disjointed, indicating that the carbon wall of the CNF contains defects. EELS spectra for the elemental analysis were acquired from the CNF shown within the broken black circle in Figure 2a. The EELS spectra, shown in Figure 2c, confirm that the energy loss near the edge see more structure originated from Sn and C and that the CNF was made of Sn and C. Furthermore, Sn mapping of the Sn-filled CNF area shown in Figure 3 (top panel) was performed. The results of the Sn mapping, shown in Figure 3 (bottom panel), confirm the existence of Sn in MK5108 the internal space of the CNF as well as in the carbon wall. The intensity of Sn in the carbon wall area was smaller than that around the central axis of the CNF, and this result showed that the amount of Sn in the carbon wall is seen to be lower than that around the central axis of the CNF. The above results reveal the successful growth of Sn-filled CNFs and the existence of Sn in the carbon walls of the grown CNFs. Figure 2 TEM image of Sn-filled CNF, high-resolution TEM image of carbon wall, and EELS spectra. (a) TEM image of Sn-filled CNF, (b) high-resolution TEM image of the Ribonucleotide reductase carbon
wall around the surface area of the Sn-filled CNF, and (c) EELS spectra from the area enclosed by a broken circle in Figure 2a. Figure 3 TEM image and Sn map of Sn-filled CNF. Although many articles have reported the growth of metal-filled CNFs [12, 15–17], the present study describes the first successful growth of Sn-filled CNFs on a Si substrate by MPCVD. Moreover, our results reveal the existence of Sn not only in the internal spaces of the Sn-filled CNFs but also in their carbon walls. The metal filling mechanism
in the internal spaces of the CNFs was considered almost the same as that reported by Hayashi et al., in which metal is introduced to the internal space by a capillary effect during CNF growth . Here, we discuss the reasons for the existence of Sn in the carbon wall. When the substrate was annealed, the Sn on the substrate formed particles. The plasma was then ignited, and the growth process began. The ions in the plasma collided with the surfaces of the Sn particles. Although these collisions increase the surface temperature of the particles, the exact temperature of the Sn particles was not determined. However, the surface temperature of the Sn particles is believed to have been approximately the same as the plasma temperature (several thousands of degrees Celsius ) because the substrate was covered completely by the plasma. The introduction of Sn into the carbon walls of the CNFs under these conditions could be explained by various phenomena.