Field Emission Cathodes Based on Structured Carbon Nanotube Arrays

Field emission properties of the structured carbon nanotube cathodes were investigated by field emission scanningnbsp microscopy, scanning electron microscopy and integral field emission measurements with luminescence screen. The carbon nanotube arrays were synthesized by the atmospheric pressure floating catalyst chemical vapour deposition method under the high temperature pyrolysis of ferrocene/xylene solution. Varying arrays of carbon nanotube columns and blocks were fabricated on Si, SiO2 and porous anodic alumina substrates.nbsp Well-aligned field emission from nearly 100% of the patches at electric field lt10 V/microm in direct current and pulsed mode integrally and locally was observed. High current capabilities up to mA currents for structured carbon nanotube cathodes were achieved. Integral field emission measurements with luminescence screen and processing under N2 and O2 exposures of up to 3times10minus5 mbar demonstrated homogeneous current distribution and long-term stability of the structured carbon nanotube cathodes.nbs