摘要:

Some reasons that require modifying the Fowler–Nordheim theory of field emission, especially for nanoscale emitters, are described. One such reason is that the microtip apex curvature radius can become comparable or even less than the width of the potential barrier on the metal–vacuum boundary. Therefore, the electric field near the surface is not homogeneous. Such deviation of the barrier shape from the traditional plane model and of the interaction between the electron and image charge must have an influence upon the emission characteristics. The possible approaches to this problem are reviewed. The results of the numerical solution of Schrödinger equation for electron tunneling, that allows us to calculate the emission current density and energy distribution of emitted electrons for arbitrary barrier shape, are presented. The problem of comparing the obtained results with the prediction of conventional Fowler–Nordheim theory is discussed.

ISSN:1071-1023    

DOI:10.1116/1.589929

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A circuit model for a field emission triode has been proposed. The model parameters have been extracted from the fabricated silicon tip array and verified by being compared to the results simulated by circuit simulator (SPICE). The cutoff frequency can be calculated from the parametric capacitance and the transconductance values extracted from measurements. For the field emission triode, the capacitance of 3.45 fF/tip and the transconductance of 0.94 nS/tip have been measured under the emission current of 4.1 nA/tip. From these values, the cutoff frequency is predicted to be 43 kHz but the measured one came out to be 6 kHz because of the parasitic capacitance components.

ISSN:1071-1023    

DOI:10.1116/1.589930

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

An effective three-dimensional finite element method analysis of electrical field is performed to obtain electric fields at field emitter tips in an array form. Considering the periodic characteristic of tips in an array form, the region for numerical analysis is reduced to a single cell with proper Neumann and Dirichlet boundary conditions. The evolution strategy is also adopted to find the optimal design condition. As an example, the maximum current density per anode area is found by the evolution strategy with design parameters of tip height and tip spacing.

ISSN:1071-1023    

DOI:10.1116/1.589931

出版商:American Vacuum Society    

年代:1998

数据来源: AIP