Nanotubes in boron nitride laser heated at high pressure

Abstract

Here we report on the finding of pure boron nitride (BN) nanotubes that do not contain any additional inclusions and on a new method for their growth: laser heating of boron nitrides at high nitrogen pressure (5–15 GPa). The multiwalled nanotubes were observed using high resolution electron microscopy and were chemically characterized by electron energy loss spectroscopy. The circular or polygonal cross-sectional nanotubes, which have 3–8 shells and a characteristic outer dimension cross section of 3–15 nm, were found to have grown either in melted cubic BN or in hexagonal+amorphous BN that had recrystallized on the specimen’s surface from the fluid phase.