Field emission in nanotubes with the length of several nanometers

We consider the problem of field emission based on carbon nanotubes (CNT), which length differs from several nanometers up to dozens of nanometers. The particle transmission function is obtained, considering the difference of potentials on the ends of CNT to be $U$ = 2–3.5 V. The value of the emission current is calculated according to the obtained transmission function. We establish the dependence of the Nordheim function on the length of nanoparticles. We consider the limiting transition for the transmission coefficient for field emission from the cathode surface in the absence of nanoparticles on it. Linear dependence of the electrical current envelopes $I$ on the field strength $W$ is obtained.