Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions

Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions

Abstract The electron emission by micro-protrusions has been studied for over a century, but the complete explanation of the unstable behaviors and their origin remains an open issue. These systems often evolve towards vacuum breakdown, which makes experimental studies of instabilities very difficul...

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Autores principales: Darius Mofakhami, Benjamin Seznec, Tiberiu Minea, Romaric Landfried, Philippe Testé, Philippe Dessante
Formato: article
Lenguaje:EN
Publicado: Nature Portfolio 2021
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Acceso en línea:https://doaj.org/article/47b128ffc87d479daa876b7f8d7e13b2
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spelling oai:doaj.org-article:47b128ffc87d479daa876b7f8d7e13b22021-12-02T18:46:55ZUnveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions10.1038/s41598-021-94443-72045-2322https://doaj.org/article/47b128ffc87d479daa876b7f8d7e13b22021-07-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-94443-7https://doaj.org/toc/2045-2322Abstract The electron emission by micro-protrusions has been studied for over a century, but the complete explanation of the unstable behaviors and their origin remains an open issue. These systems often evolve towards vacuum breakdown, which makes experimental studies of instabilities very difficult. Modeling studies are therefore necessary. In our model, refractory metals have shown the most striking results for discontinuities or jumps recorded on the electron emitted current under high applied voltages. Herein, we provide evidence on the mechanisms responsible for the initiation of a thermal instability during the field emission from refractory metal micro-protrusions. A jump in the emission current at steady state is found beyond a threshold electric field, and it is correlated to a similar jump in temperature. These jumps are related to a transient runaway of the resistive heating that occurs after the Nottingham flux inversion. That causes the hottest region to move beneath the apex, and generates an emerging heat reflux towards the emitting surface. Two additional conditions are required to initiate the runaway. The emitter geometry must ensure a large emission area and the thermal conductivity must be high enough at high temperatures so that the heat reflux can significantly compete with the heat diffusion towards the thermostat. The whole phenomenon, that we propose to call the Nottingham Inversion Instability, can explain unexpected thermal failures and breakdowns observed with field emitters.Darius MofakhamiBenjamin SeznecTiberiu MineaRomaric LandfriedPhilippe TestéPhilippe DessanteNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-12 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Darius Mofakhami
Benjamin Seznec
Tiberiu Minea
Romaric Landfried
Philippe Testé
Philippe Dessante
Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions
description Abstract The electron emission by micro-protrusions has been studied for over a century, but the complete explanation of the unstable behaviors and their origin remains an open issue. These systems often evolve towards vacuum breakdown, which makes experimental studies of instabilities very difficult. Modeling studies are therefore necessary. In our model, refractory metals have shown the most striking results for discontinuities or jumps recorded on the electron emitted current under high applied voltages. Herein, we provide evidence on the mechanisms responsible for the initiation of a thermal instability during the field emission from refractory metal micro-protrusions. A jump in the emission current at steady state is found beyond a threshold electric field, and it is correlated to a similar jump in temperature. These jumps are related to a transient runaway of the resistive heating that occurs after the Nottingham flux inversion. That causes the hottest region to move beneath the apex, and generates an emerging heat reflux towards the emitting surface. Two additional conditions are required to initiate the runaway. The emitter geometry must ensure a large emission area and the thermal conductivity must be high enough at high temperatures so that the heat reflux can significantly compete with the heat diffusion towards the thermostat. The whole phenomenon, that we propose to call the Nottingham Inversion Instability, can explain unexpected thermal failures and breakdowns observed with field emitters.
format article
author Darius Mofakhami
Benjamin Seznec
Tiberiu Minea
Romaric Landfried
Philippe Testé
Philippe Dessante
author_facet Darius Mofakhami
Benjamin Seznec
Tiberiu Minea
Romaric Landfried
Philippe Testé
Philippe Dessante
author_sort Darius Mofakhami
title Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions
title_short Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions
title_full Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions
title_fullStr Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions
title_full_unstemmed Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions
title_sort unveiling the nottingham inversion instability during the thermo-field emission from refractory metal micro-protrusions
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/47b128ffc87d479daa876b7f8d7e13b2
work_keys_str_mv AT dariusmofakhami unveilingthenottinghaminversioninstabilityduringthethermofieldemissionfromrefractorymetalmicroprotrusions
AT benjaminseznec unveilingthenottinghaminversioninstabilityduringthethermofieldemissionfromrefractorymetalmicroprotrusions
AT tiberiuminea unveilingthenottinghaminversioninstabilityduringthethermofieldemissionfromrefractorymetalmicroprotrusions
AT romariclandfried unveilingthenottinghaminversioninstabilityduringthethermofieldemissionfromrefractorymetalmicroprotrusions
AT philippeteste unveilingthenottinghaminversioninstabilityduringthethermofieldemissionfromrefractorymetalmicroprotrusions
AT philippedessante unveilingthenottinghaminversioninstabilityduringthethermofieldemissionfromrefractorymetalmicroprotrusions
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