We report the growth and detailed structural investigation of a new morphological manifestation of carbon-based nanostructures in the form of tapered whiskers with uniform 1−3 nm hollowness. The base of the whiskers is in the submicron scale, tapering uniformly to form a pointed tip in the form of a pipette. These hollow nanopipettes have a shell containing helical graphitic sheets. We propose that these whiskers grow by competing phenomena of growth and etching that control their aspect ratio.

Single-crystal electron nanodiffraction patterns have been obtained from nanocrystals of various phases formed within carbonaceous balls produced by chemical vapor deposition (CVD). For the face-centered cubic phase, n-diamond, with cell dimension a = 0.36 nm, the relative intensities of the (200) reflection (forbidden for the diamond structure) and the (111) reflection suggest that the structure may include hydrogen atoms, and theoretical analyses support this possibility. There is evidence for a body-centered cubic phase with a = 0.31 nm, and the incorporation of hydrogen in this structure is suggested. Small amounts of hexagonal diamond, i-carbon, and other cubic phases are also present.

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