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Simulation of the Influence of Interface Charge on Electron Emission

Published online by Cambridge University Press:  14 March 2011

Kevin L. Jensen
Affiliation:
Code 6840, ESTD, Naval Research Laboratory Washington, DC 20375-5347, USA
Jonathan L. Shaw
Affiliation:
Code 6840, ESTD, Naval Research Laboratory Washington, DC 20375-5347, USA
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Abstract

Several materials are promising candidates for electron sources. For diamond, a tunneling interface at the back contact limits injecting charge into the conduction band, but a purely geometric model of internal field emission is inadequate to explain experimental data. The presence of a defect, modeled by a coulomb charge, within the tunneling barrier region significantly enhances transmission and, in concert with a geometrical model, may better account for observed current levels. Charge has been suggested to play a similar role in the SiO2 covering on a single tip silicon field emitter to explain experimental data. The tunneling theory in both cases is similar. In the present work, a general method for estimating electron transport and energy distributions through potential profiles, which describe both semiconductor interfaces and field emission potential barriers when a charged particle modifies the tunneling barrier, is developed. While the model is intended for treating a metal-semiconductor interface, it is cast here in terms of in a thin SiO2 coating over a silicon field emitter tip to enable qualitative comparisons with experimental data. Tunneling probabilities are found by numerically solving Schrödinger's Equation for a piece-wise linear potential using an Airy Function approach. A qualitative comparison to experimental energy distribution findings is possible by utilizing an analytical model of the field emitter tip from which current-voltage relations may be found.

Type
Research Article
Copyright
Copyright © Materials Research Society 2000

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References

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