Synthesis, Physical Property Control and Electronic Application of Carbon Nanotubes and Nanocapsules

对碳纳米管和氮化硼纳米管的合成和结构表征进行了广泛的研究，并对碳纳米管的场发射及其在显示器件中的应用进行了研究。获得了以下成果：1。研究了单壁碳纳米管（SWCNTs）催化剂的高效制备和直径控制，发现了Rh-Pt、La-Ni和Ce-Ni是高效的双金属催化剂。随着电弧反应器中氦压力的降低，单壁碳纳米管的直径逐渐减小。平均直径从1.02 nm （50 Torr He）到1.5nm （1520 Torr He）。缓冲气体对多壁碳纳米管（MWCNTs）生长的影响即使在氧气和空气的气氛中，MWCNTs也通过电弧放电生长。在这些气体中产生的MWCNTs比在氦气中产生的MWCNTs含有更少的杂质，如石墨碎片。氮化硼（BN）纳米管的生长与结构表征采用氮气氛中二硼化锆电极间电弧放电的方法合成了六方氮化硼纳米管。在其尖端观察到BN纳米管的新形态，表明存在能量不利的奇元环。碳纳米管的场发射及其作为显示器件电子源的应用盖帽MWCNT的场发射显示出五角形电子发射的场发射模式，并且在模式中还观察到相邻五角形发出的电子波之间的干涉条纹。观察了分子在纳米管尖端的吸附和解吸过程，揭示了分子的吸附和解吸是引起发射电流波动的主要原因。研究了不同气体条件下纳米管场致发射体的寿命。在此基础上，实验制备了纳米管基场发射显示器件。

Synthesis and structural characterization of carbon nanotubes and boron nitride nanotubes are extensively performed, and studies of field emission from carbon nanotubes and its application to display devices are carried out. The following achievements are obtained.1. Efficient production and diameter control of single-wall carbon nanotubes (SWCNTs)Catalysts that work efficiently to produce SWCNTs by electric arc discharge are searched, and Rh-Pt, La-Ni and Ce-Ni are found efficient bimetallic catalysts. The diameters of SWNTs is found to decrease with the reduction of helium (He) pressure in the arc reactor. The average diameter varies from 1.02 nm (for 50 Torr He) to 1.5nm (for 1520 Torr He).2. Effect of buffer gases on the growth of multiwall carbon nanotubes (MWCNTs)Even in an atmosphere of oxygen and air, MWCNTs grow by arc discharge. MWCNTs produced in these gases contain less impurities such as graphite debris than those produced in helium gas.3. Growth and structure characterization of boron nitride (BN) nanotubesNanotubes of hexagonal-BN are synthesized by arc discharge between zirconium diboride electrodes in nitrogen atmosphere. New morphology of BN nanotubes at their tips, suggesting the presence of energetically unfavorable odd-membered rings, was observed.4. Field emission from carbon nanotubes and its application as electron sources of display devicesField emission of electrons from a capped MWCNT exhibits field emission patterns suggesting electron emission from pentagons, and interference fringes between electron waves emanating from adjacent pentagons are also observed in the patterns. Adsorption and desorption of molecules on a nanotube tip are observed, and it is revealed that they are responsible for fluctuation in emission current. Lifetime of nanotube field emitters are investigated under various gas species. Developing these studies, nanotube-base field emission display devices are experimentally fabricated.