Numerous fullerenes were synthesized in various B-C-N materials by in-situ
electron beam irradiation in a high-resolution transmission analytical elec
tron microscope JEM-3000F. Boron-doped graphitic carbons, hexagonal and rho
mbohedral boron nitrides, and ternary B-C-N turbostratic materials served a
s the starting materials for irradiation. The transformation to fullerene-l
ike morphology from originally flat or curled and jumbled graphene-like she
ets or polygonal particles takes place through a solid-state phase transiti
on by rearrangement of atoms, which is drastically enhanced by thermal and
irradiation-induced diffusion. The scale of generated fullerenes ranges fro
m similar to 1 nm (single-shelled objects) to 50 nm (giant nested objects h
aving up to 75 shells). Fullerene symmetry and chemical composition were cl
arified by high-resolution transmission electron microscopy and electron en
ergy loss spectroscopy, respectively. Finally, 3-D fullerene models were de
veloped which particularly emphasize icosahedral symmetry for B-C and B-C-N
fullerenes, and octahedral symmetry for BN fullerenes.