Field nanoemitters:Ultrathin BN nanosheets protruding from Si 3N4 nanowires

Field emitters in nanoscale are important in micro/nanoelectronic devices. Here, we report a large scale synthesis and effective field emission of field nanoemitters. The integrated nanostructures of ultrathin BN nanosheets aligned on Si3N4 nanowires are prepared through a two-stage process. Si3N4 nanowires were previously synthesized through heating Si powder at 1500°C under a N2 atmosphere. Ultrathin BN nanosheets were then deposited on Si3N4 nanowires by heating a homemade B-N-O precursor under a N2/NH 3 atmosphere. The as-prepared nanofilaments act as cold electron emitters displaying excellent field emission performance owing to the untrathin and sharp edges of the protruding BN nanosheets.</p

Carbon nanotubes as nanoreactors for fabrication of single-crystalline Mg3N2 nanowires

Due to fast decomposition of Mg3N2 in the presence of water in the atmosphere (Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH3), the synthesis of single-crystalline Mg3N2 nanowires has been a challenge. Here, we demonstrate that carbon nanotubes may serve as nanoreactors for a simple thermal reaction process resulting in the first fabrication of high-quality, large-yield, single-crystalline Mg3N2 nanowires. The Mg 3N2 nanowires are homogeneously sheathed over their entire lengths with very thin graphitic carbon tubular layers, which effectively prevent their decomposition (even when the samples are put into water or exposed to atmosphere for several months). We have systematically analyzed for the first time the Mg3N2 nanomaterlal by means of transmission electron microscopy (TEM), high-resolution TEM, and electron diffraction. Successful fabrication of carbon sheath protected Mg3N2 nanowires may promote further experimental studies on their crystal structures and properties.</p