Thin-walled boron nitride microtubes exhibiting intense band-edge UV emission at roomtemperature

Abstract

Boron nitride (BN) microtubes were synthesized in a vertical induction furnace usingLi2CO3 and B reactants. Their structures and morphologies were investigatedusing x-ray diffraction, scanning and transmission electron microscopy, andenergy-dispersive x-ray spectroscopy. The microtubes have diameters of1–3 µm, lengths of up to hundreds of micrometers, and well-structured ultrathin walls only∼50 nm thick. A mechanism combining the vapor–liquid–solid (VLS) and template self-sacrificing processesis proposed to explain the formation of these novel one-dimensional microstructures, in which theLi2O–B2O3 eutectic reaction plays an important role. Cathodoluminescence studies show that even at roomtemperature the thin-walled BN microtubes can possess an intense band-edge emission at∼216.5 nm, which is distinct compared with other BN nanostructures. The study suggests that thethin-walled BN microtubes should be promising for constructing compact deep UV devicesand find potential applications in microreactors and microfluidic and drug delivery systems.