Ab initio study of negative electron affinity on the scandium-terminated diamond (100) surface for electron emission devices

Ramiz Zulkharnay; Neil L. Allan; Paul W. May

doi:10.1016/j.carbon.2022.04.067

Ab initio study of negative electron affinity on the scandium-terminated diamond (100) surface for electron emission devices

Ramiz Zulkharnay^*, Neil L. Allan, Paul W. May

^*Corresponding author for this work

Research output: Contribution to journal › Article (Academic Journal) › peer-review

10 Citations (Scopus)

Abstract

Surface modification of diamond with the addition of (sub)monolayer of metals or other electropositive adsorbates than the bulk carbon can result in negative electron affinity (NEA). Surface coverages of up to one-monolayer (<1 ML) of scandium on clean, oxygenated and nitrogenated diamond (100) surfaces were studied via plane-wave density functional theory (DFT) calculations. Adsorption of Sc on diamond is energetically favourable; for example, 0.25 ML coverage of Sc on the oxygenated diamond (100) surface has an extremely large calculated adsorption energy per adsorbate atom of −8.68 eV. Moreover, the majority of stable Sc-adsorption configurations possess NEA, with the most negative values of −3.73 eV, – 3.02 eV and −1.75 eV being found for 0.25 ML Sc coverage on the oxygenated, bare and nitrogenated diamond surfaces, respectively. These results predict that Sc termination on diamond should provide a thermally stable surface with large NEA, and is therefore a highly promising candidate for thermionic and other electron-emission applications.

Original language	English
Pages (from-to)	176-185
Number of pages	10
Journal	Carbon
Volume	196
Early online date	2 May 2022
DOIs	https://doi.org/10.1016/j.carbon.2022.04.067
Publication status	Published - 30 Aug 2022

Bibliographical note

Funding Information:
RZ would like to acknowledge the funding scheme of the Government of the Republic of Kazakhstan under the Bolashak International programme. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol (http://bris.ac.uk/acrc/).

Funding Information:
RZ would like to acknowledge the funding scheme of the Government of the Republic of Kazakhstan under the Bolashak International programme. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol ( http://bris.ac.uk/acrc/ ).

Publisher Copyright:
© 2022

Keywords

Density functional theory
Diamond
Negative electron affinity
Scandium
Surface
Thermionic electron emission

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10.1016/j.carbon.2022.04.067

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4045832

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10 Citations
3 Article (Academic Journal)

Enhanced Electron Emission Performance and Air-Surface Stability in ScO-Terminated Diamond for Thermionic Energy Converters
Zulkharnay, R., Fox, N. A. & May, P. W., 2 Sept 2024, (E-pub ahead of print) In: Small. 20, 48, 2405408.
Research output: Contribution to journal › Article (Academic Journal)

Open Access
Oxygen-terminated diamond: insights into the correlation between surface oxygen configurations and work function values
Zulkharnay, R., Zulpukarova, G. & May, P. W., 15 Jun 2024, In: Applied Surface Science. 658, 9 p., 159776.
Research output: Contribution to journal › Article (Academic Journal) › peer-review

Open Access
6 Citations (Scopus)
Experimental studies of electron affinity and work function from titanium on oxidised diamond (100) surfaces
Fogarty, F., Fox, N. A. & May, P. W., 31 Dec 2022, In: Functional Diamond. 2, 1, p. 103-111 9 p.
Research output: Contribution to journal › Article (Academic Journal) › peer-review

Open Access

Cite this

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title = "Ab initio study of negative electron affinity on the scandium-terminated diamond (100) surface for electron emission devices",

abstract = "Surface modification of diamond with the addition of (sub)monolayer of metals or other electropositive adsorbates than the bulk carbon can result in negative electron affinity (NEA). Surface coverages of up to one-monolayer (<1 ML) of scandium on clean, oxygenated and nitrogenated diamond (100) surfaces were studied via plane-wave density functional theory (DFT) calculations. Adsorption of Sc on diamond is energetically favourable; for example, 0.25 ML coverage of Sc on the oxygenated diamond (100) surface has an extremely large calculated adsorption energy per adsorbate atom of −8.68 eV. Moreover, the majority of stable Sc-adsorption configurations possess NEA, with the most negative values of −3.73 eV, – 3.02 eV and −1.75 eV being found for 0.25 ML Sc coverage on the oxygenated, bare and nitrogenated diamond surfaces, respectively. These results predict that Sc termination on diamond should provide a thermally stable surface with large NEA, and is therefore a highly promising candidate for thermionic and other electron-emission applications.",

keywords = "Density functional theory, Diamond, Negative electron affinity, Scandium, Surface, Thermionic electron emission",

author = "Ramiz Zulkharnay and Allan, {Neil L.} and May, {Paul W.}",

note = "Funding Information: RZ would like to acknowledge the funding scheme of the Government of the Republic of Kazakhstan under the Bolashak International programme. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol (http://bris.ac.uk/acrc/). Funding Information: RZ would like to acknowledge the funding scheme of the Government of the Republic of Kazakhstan under the Bolashak International programme. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol ( http://bris.ac.uk/acrc/ ). Publisher Copyright: {\textcopyright} 2022",

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AU - Zulkharnay, Ramiz

AU - Allan, Neil L.

AU - May, Paul W.

N1 - Funding Information: RZ would like to acknowledge the funding scheme of the Government of the Republic of Kazakhstan under the Bolashak International programme. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol (http://bris.ac.uk/acrc/). Funding Information: RZ would like to acknowledge the funding scheme of the Government of the Republic of Kazakhstan under the Bolashak International programme. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol ( http://bris.ac.uk/acrc/ ). Publisher Copyright: © 2022

PY - 2022/8/30

Y1 - 2022/8/30

N2 - Surface modification of diamond with the addition of (sub)monolayer of metals or other electropositive adsorbates than the bulk carbon can result in negative electron affinity (NEA). Surface coverages of up to one-monolayer (<1 ML) of scandium on clean, oxygenated and nitrogenated diamond (100) surfaces were studied via plane-wave density functional theory (DFT) calculations. Adsorption of Sc on diamond is energetically favourable; for example, 0.25 ML coverage of Sc on the oxygenated diamond (100) surface has an extremely large calculated adsorption energy per adsorbate atom of −8.68 eV. Moreover, the majority of stable Sc-adsorption configurations possess NEA, with the most negative values of −3.73 eV, – 3.02 eV and −1.75 eV being found for 0.25 ML Sc coverage on the oxygenated, bare and nitrogenated diamond surfaces, respectively. These results predict that Sc termination on diamond should provide a thermally stable surface with large NEA, and is therefore a highly promising candidate for thermionic and other electron-emission applications.

AB - Surface modification of diamond with the addition of (sub)monolayer of metals or other electropositive adsorbates than the bulk carbon can result in negative electron affinity (NEA). Surface coverages of up to one-monolayer (<1 ML) of scandium on clean, oxygenated and nitrogenated diamond (100) surfaces were studied via plane-wave density functional theory (DFT) calculations. Adsorption of Sc on diamond is energetically favourable; for example, 0.25 ML coverage of Sc on the oxygenated diamond (100) surface has an extremely large calculated adsorption energy per adsorbate atom of −8.68 eV. Moreover, the majority of stable Sc-adsorption configurations possess NEA, with the most negative values of −3.73 eV, – 3.02 eV and −1.75 eV being found for 0.25 ML Sc coverage on the oxygenated, bare and nitrogenated diamond surfaces, respectively. These results predict that Sc termination on diamond should provide a thermally stable surface with large NEA, and is therefore a highly promising candidate for thermionic and other electron-emission applications.

KW - Density functional theory

KW - Diamond

KW - Negative electron affinity

KW - Scandium

KW - Surface

KW - Thermionic electron emission

U2 - 10.1016/j.carbon.2022.04.067

DO - 10.1016/j.carbon.2022.04.067

M3 - Article (Academic Journal)

AN - SCOPUS:85129286342

SN - 0008-6223

VL - 196

SP - 176

EP - 185

JO - Carbon

JF - Carbon

ER -

Ab initio study of negative electron affinity on the scandium-terminated diamond (100) surface for electron emission devices

Abstract

Bibliographical note

Keywords

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Research output

Enhanced Electron Emission Performance and Air-Surface Stability in ScO-Terminated Diamond for Thermionic Energy Converters

Oxygen-terminated diamond: insights into the correlation between surface oxygen configurations and work function values

Experimental studies of electron affinity and work function from titanium on oxidised diamond (100) surfaces

Cite this