Size-controlled short nanobells: Growth and formation mechanism

Very short nanofibers containing only a few nanobells have been produced fr om nitrogen-doped carbon nanotubes by two methods, H-2 plasma treatment, fo llowed by grinding and oxidation with acidified potassium permanganate. The length of these short nanofibers can be controlled to give a wide range of sizes. The shortest nanofibers are composed of only a single nanobell with dimensions of similar to 15 nm in diameter and length. High-resolution tra nsmission electron microscope images reveal that their structures are close d at one end and open at the other. The formation mechanism of these short nanofibers and individual nanobells is discussed along with their potential for interesting nanotube-end physics and chemistry. (C) 2000 American Inst itute of Physics. [S0003-6951(00)00751-8].