| United States Patent | 5,457,343 |
| Ajayan, et. al. | Oct. 10, 1995 |
| Inventors: | Ajayan; Pulickel M. (Tokyo, JP); Iijima; Sumio (Tokyo, JP). |
| Assignee: | NEC Corporation (Tokyo, JP). |
| Appl. No.: | 170,806 |
| Filed: | Dec. 21, 1993 |
| Dec. 22, 1992 [JP] | 4-341747 |
| Intl. Cl.: | H01L 29/41; H01L 29/43; D01F 9/12 |
| U.S. Cl.: | 257/734; 257/741; 257/746; 423/447.2; 423/DIG.39; 423/DIG.40 |
| Field of Search: | 257/734, 741-742, 1-4, 746; 422/312; 423/447.2, DIG. 39, DIG. 40; 428/367, 371, 376, 377 |
| 5,346,683 | Sept., 1994 | Green et al. | 423/447.2 |
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The invention provides a nanometer sized carbon tubule enclosing a foreign material except for carbon. The carbon tubule comprises a plurality of tubular graphite monoatomic sheets coaxially arranged. The foreign material is introduced through a top portion of the carbon tubule. The introduction of the foreign material is accomplished after forming an opening at the top portion of the carbon tubule either by contacting the foreign material with the top portion of the carbon tubule together with a heat treatment or by an evaporation of the foreign material on the top portion of the carbon tubule together with the heat treatment. The foreign material is introduced only in a center hollow space defined by an internal surface of the most inner tubular graphite monoatomic sheet.