Field electron emission from nanotube carbon layers grown by CVD process

We present the field emission characteristics of nanotube carbon layers gro wn by chemical vapor deposition process. In this process, products of therm al decomposition of polyethylene were used as the source of carbon. SEM and HREM investigations of manufactured layers showed that these layers consis ted of randomly oriented conical layer carbon nanotubes (CLNTs). The diamet er of nanotubes usually ranged from 20 up to 40 nm. The investigations of f ield electron emission were fulfilled at room and low (approximate to 120 K ) temperatures. The emission current of 0.1 nA arose at the average electri c field E-av = 1.5-2.5 V/mum. The emission current of 100 muA (current dens ity, approximate to 10 mA/cm(2)) was observed at E-av = 4 - 4.5 V/mum. The value of field amplification coefficient beta was equal to 1300-2000. The f ield emission characteristics replotted in Fowler-Nordheim coordinates were linear at room and low (approximate to 120 K) temperatures for current var iation of 5-6 orders of magnitude. The calculations of field amplification coefficient beta were fulfilled for an array of aligned closed nanotubes. T hese calculations demonstrated strong dependence of beta versus the distanc e between nanotubes and their height. (C) 2001 Published by Elsevier Scienc e B.V.