Adjustable boron carbonitride nanotubes

The adjustable photoluminescence (PL) and field electron emission (FEE) properties of boron carbonitride (B-C-N) nanotubes grown under well-controlled conditions are studied systematically. Large-scale highly aligned B-C-N nanotubes are synthesized directly on Ni substrates by the bias-assisted hot filament chemical vapor deposition method. Single-walled B-C-N nanotubes and nanometric B-C-N heterojunctions are obtained by the pulsed-arc-discharge technique and pause-reactivation two-stage process, respectively. It is found that the microstructures, orientations, and chemical compositions of the nanotubes can be controlled by varying growth parameters. The mechanism of the controllable growth is also investigated. Intense and stable PL from the nanotubes is observed in both blue-violet (photon energies 3.14-2.55 eV) and yellow-green bands (photon energies 2.13-2.34 eV) and the emission bands are adjusted by varying the compositions of the nanotubes. FEE properties are also studied and optimized by varying the B or N atomic concentrations in the nanotubes. All these results verify the controllability of the electronic band structure of the B-C-N nanotubes. (C) 2002 American Institute of Physics.