Dynamical resonance tunnelling—a theory of giant emission from carbon field emitters

Abstract

Abstract. The classic theory of electron field emission from a cold metal surface due to Fowler and Nordheim (FN) is re-examined and found to violate the validity criteria for the WKB approximation, for electric fields greater than about 1 V/µm. In this study we shall examine the complete solution without invoking the WKB approximation in order to assess the reliability of the FN theory as widely used for the interpretation of experimental data. Particular problems occur when the barrier height (and therefore indirectly also the width) is significantly reduced by the image or some external effects. Further refinement of the theory will be discussed by considering the effects of screening, which can be one mechanism for the barrier height reduction, in addition to the widely known negative affinity of diamond like carbon systems. A comparison with experimental data from carbon field emitters shows that the enhanced current found in this paper may provide an explanation for strong field emission observed recently in carbon based samples.

Synthesis of Rh–carbon nanotube based heterostructures and their enhanced field emission characteristics

“…4 Unfortunately, their higher resistivity diminishes their replenishment and transport of electrons, thereby requiring higher threshold fields with time to sustain a constant emission current. 5 Since carbon nanotubes are already considered to be good emitters, 6 their desirable properties may be further enhanced by making use of the electronic properties (work function and the structure of density of states) of metal decorated CNT heterostructures since some of these can operate remarkably well (lower applied voltages) below the intrinsic current limit due to their thermal effects. 7 Current strategies of binding nanoparticles to carbon nanotubes (CNTs) often make use of small organic bridging molecules to improve the adhesion between the nanostructures and CNTs.…”