Self-assembly and cathodoluminescence of microbelts from Cu-doped boron nitride nanotubes

We report the self-assembly of microbelts from Cu-doped boron nitride nanotubes by chemical vapor deposition using Cu as a catalyst. The BN nanotubes with Cu-encapsulated flat tips have uniform outer diameters of similar to 240 nm, inner diameters of similar to 210 nm, and lengths of similar to 10 mu m and Cu is found to uniformly dope into the nanotubes. Most importantly, the nanotubes are self-assembled to form microbelts with 10 mu m in width and tens of micrometers in length. Strong and tunable light emissions from the ultraviolet to visible light range are observed in such Cu-doped microbelts, showing their high potential for applications in lasing, light-emitting diode, and medical diagnosis devices.