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

Abstract

Boron nitride (BN) microtubes were synthesized in a vertical induction furnace using Li<inf>2</inf>CO<inf>3</inf> and B reactants. Their structures and morphologies were investigated using x-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The microtubes have diameters of 1-3 νm, 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 processes is proposed to explain the formation of these novel one-dimensional microstructures, in which the Li<inf>2</inf>O-B<inf>2</inf>O<inf>3</inf> eutectic reaction plays an important role. Cathodoluminescence studies show that even at room temperature 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 the thin-walled BN microtubes should be promising for constructing compact deep UV devices and find potential applications in microreactors and microfluidic and drug delivery systems. © 2009 IOP Publishing Ltd.