C-BN patterned single-walled nanotubes synthesized by laser vaporization.

We report on the synthesis of C-BN single-walled nanotubes made of BN nanodomains embedded into a graphene layer. The synthesis process consists of vaporizing, by a continuous CO2 laser, a target made of carbon and boron mixed with a Co/Ni catalyst under N2 atmosphere. High-resolution transmission electron microscopy (HRTEM) and nanoelectron energy loss spectroscopy (nanoEELS) provide direct evidence that boron and nitrogen co-segregate with respect to carbon and form nanodomains within the hexagonal lattice of the graphene layer in a sequential manner. A growth model is proposed to account for the observed C-BN self-organization and to explain how kinetics and local energetics at intermediate states can tailor ultimate single layer BN-C heterojunctions.