Study on field enhancement of a normal-gated field emission nanowire cold cathode

Abstract

The field enhancement is one of the important factors that indicate the performance of field emission cold cathode devices. It is intimately related to the field emission current density and the threshold voltage of the device. In our paper, the field enhancement factor of a normal-gated field emission nanowire cold cathode model was analytically deduced on the basis of classical electrostatic theory, and it is given by the equation. β=k1{N2·(L-d1)2+［1/k1+(L-d1)］2}1/2. The effect of geometrical parameters of the device on the field enhancement factor was explored. The theoretical analysis showed that the larger the length (L-d1) of nanowire above the gate and the gate hole radius, the larger the enhancement factor is; but the larger the nanowire radius, the smaller the enhancement factor is. When the L is much larger thand1, the enhancement factor satisfies the relation. β∝Ｌ／r0, for which N=N1(k1r0)/N0(k1r0), N0(k1r0) and N1(k1r0) are both Neumann functions and k1=0.8936/R. R, L, r0 and d1 are the gate hole radius, the nanowire length, the nanowire radius and the gate-cathode distance, respectively.

Study on Field Emission Characteristics of Normal-Gated and Under-Gated Carbon Nanotube Cold Cathode

“…Considering its symmetry, the following expression of potential ϕ can be obtained, this consistent with the former conclusion [9,[18][19].…”

“…However, it is difficult for the diode structure to work with IC, because the diode structure needs higher control voltage. At present, triode-type structure has been proposed, and its superiority has been demonstrated comparing with diode structure [16][17][18]. Consequently, the study of field emission properties of triode-type structure is become the hot research tropics in this area and is concerned widely.…”

Field emission of carbon nanotube array with normal-gate cold cathode

“…which is consistent with the former conclusion. [19] The initial and boundary conditions can be expressed as ϕ| z=0 = 0, ϕ| z=dag+dcg+dg = V a , ϕ| r=R z=dcg+dg = V g , ϕ| z=L,0≤r≤r0 = 0, and ϕ| r=r0,0≤Z≤L = 0.…”

“…A large number of electrons could be emitted from the cold cathode due to a strong electric field in FED. [19] The total emission current and the number of electrons impinging on the anode layer can be controlled easily by adjusting the gate voltage. The curves for enhancement factor β versus gate voltage with different values of gate radius R are shown in Fig.…”