Electron field emission from boron-nitride nanofilms

Hexagonal polycrystalline boron-nitride (BN) films are synthesized on Si substrates by plasma-assisted chemical-vapor deposition. In the case of BN films thicker than 20 nm, the turn-on electric field of the electron emission decreases with increasing surface roughness. On the other hand, in the case of BN film as thin as 8-10 nm, it is found that the turn-on electric field is reduced to 8.3 V/mum in spite of the surface of the BN nanofilm being flat, as well as the Si substrate. The Fowler-Nordheim (FN) plot of the field-emission characteristics of the BN nanofilm indicates a straight line, suggesting the presence of FN tunneling. This finding means that introduction of the BN nanofilm leads to a significant reduction in the effective potential barrier height. (C) 2002 American Institute of Physics.