Field enhancement factor for an array of MWNTs in CNT paste

The simulation results of the electric field intensity and the enhancement factor, γ, for an individual CNT imaged as a conducting rod is presented. The field enhancement factor, γ̄, for the CNT paste array is evaluated experimentally by varying the cathode-anode (CA) spacing, d. The simulations indicate that the distribution of electric field intensity and the enhancement factor as a function of cathode-anode spacing, d, could be divided into the two parts: strong (d<100 μm) and weak (d>100 μm) dependences of the enhancement factor γ(d). Furthermore, the field enhancement factor, γ̄, estimated experimentally for the CNT paste FEA indicates that the two-region field emission model (TRFE) is adequate for estimation of the field enhancement factor, γ̄. Moreover, the effective enhancement factor, γ̄, for the CNT paste FEA was found to be ≈50γ and is attributed to the additions of the emission currents from the individual CNTs in an array. In addition, the empiric functions of the geometrical enhancement factor, β̄(d), and γ̄(d) were estimated from the Fowler–Nordheim plot for the CNT paste FEA. One can use the empiric functions β̄(d) and γ̄(d) for the design and fabrication of the devices based on the CNT paste FEA with a variable CA spacing. PACS 81.07.De; 85.35.Kt; 79.70.+q; 85.45.Fd; 72.80.Tm