碳纳米管作为一种新型的光电材料有着广泛的应用,可用于平板显示器中的电子发射器件.定向碳纳米管阵列是碳纳米管的一种取向形态,具有其独特的性质.与缠绕无序的碳纳米管相比,定向碳纳米管更易分散、测量和应用.文章在低压条件下采用酞菁铁高温裂解法,在800～1 000℃,以石英玻璃为基底,制备了大面积高度定向的碳纳米管.通过SEM和TEM对定向碳纳米管的结构进行分析.结果表明该法制备的碳纳米管长20 μm,管径40～70 nm,为竹节状结构的多壁碳纳米管.实验中发现系统真空度和生长温度都对定向碳纳米管生长有影响.通过对该碳纳米管进行场发射测试,结果表明此定向碳纳米管的开启电压仅为0.67 V·μm-1(I=1 μA),阈值电压为2.5 V·μm-1,具有良好的场发射性能.
Carbon nanotubes are promising as new optoeleetronic materials such as new electron field emitters in panel displays.For most of applications,it is highly desirable to prepare aligned carbon nanotubes (ACNTs) so that the properties of individual nanotubes can be easily assessed and they can be incorporated effectively into devices for the applications in panel fieldemitting displays.By pyrolysis of iron(Ⅱ) phthalocyanine (FeC32N8H16) at 800～1 000℃under low pressure(Ar/H2),large-scale of vertically aligned carbon nanotubes have been synthesized on quartz glass plates.The character and structure of ACNTs were analyzed by SEM and TEM,respectively.The results indicate that the average length of ACNTs is about 20 μm with a Iarger diameter range from 40 nm to 70 am.These ACNTs have a cylindrical and barnboo-like structure and are multi-walled carbon nanotubus.By the investigation of preparation parameters,it has been found that the system vacuum and growth temperature have larger influences on the synthesis of such nanotubes.The field emission properties of ACNTs were measured and the result shows a very powerful ability of electron emission with a turn-on voltage of 0.67 V·μm-1(I=1 μA) and a threshold voltage of 2.5 V·μm-1.
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