Field Emission Properties of Vertically Aligned Carbon Nanotubes Dependent Upon Gas Exposures and Growth Conditions

摘要

Vertically aligned carbon nanotubes have been grown with different growth conditions by microwave plasma chemical vapor deposition and thermal chemical vapor deposition. The field emission properties of such grown carbon nanotubes are studied. Carbon nanotube field emission array(CNT-FEA) under high bias voltage is exposed to hydrogen, nitrogen, and oxygen. After each exposure, changes on turn-on voltage and slope of Fowler-Nordheim plots are observed. It is observed that saturation of emission current is contributed by adsorbates on the surface of carbon nanotube emitters. Due to high electron affinity, oxygen and nitrogen degrade field emission properties, whereas the effects of nitrogen are less severe. However, emission properties are enhanced at hydrogen exposures by removing adsorbates with hydrogen atoms.