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采用等离子体增强热灯丝化学气相沉积方法 ,以甲烷和氢气为反应气体 ,在钨丝衬底上制备出准直的碳纳米纤维 (CNFs) ,其生长密度小于 10 6 cm- 2 ,长度为 6— 30 μm ,直径为 6 0— 10 0nm .并采用自制的双探针扫描电子显微镜系统 ,对所生长的单根CNF作了场发射特性研究 .结果表明 ,其场发射开启电压约为 5V μm ,相应的发射电流达到2 0 μA cm2 ,同时 ,对不同长度的CNFs及单根CNF不同位置的场发射研究表明 ,场发射电流的大小不仅与材料本身的功函数、外电场场强、材料的微观结构以及宏观的几何结构有关 ,而且电子在输运过程中所受到的散射也是决定场发射电流大小的关键因素 .
Plasma-enhanced hot filament chemical vapor deposition (CVD) was used to prepare aligned carbon nanofibers (CNFs) on tungsten substrate with methane and hydrogen as reactant gases with growth densities of less than 10 6 cm -2 and length of 6 - 30 μm and a diameter of 60-100 nm. The field emission characteristics of a single CNF grown by a self-made dual-probe scanning electron microscope were studied. The results show that the field emission voltage is about 5V μm , And the corresponding emission current reaches 20 μA cm2. At the same time, field emission studies at different positions of CNFs and single CNFs show that the field emission current is not only related to the work function of the material itself, the external electric field strength, Microstructure and macroscopic geometry, and the electron scattering during transport is also the key factor to determine the size of the field emission current.