Experimental Studies of Electron Affinity and Work Function from Aluminium on Oxidized Diamond (100) and (111) Surfaces

Paul W May*, Michael C James, Mattia Cattelan, Neil A Fox, Rui Silva, Ricardo Silva

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

1 Citation (Scopus)
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Abstract

Three different procedures were used to deposit aluminium onto O-terminated (100) and (111) boron-doped diamond, with the aim of producing a thermally stable surface with low work function and negative electron affinity. The methods were: (i) deposition of a >20 nm film Al by high-vacuum evaporation, followed by HCl acid wash to remove excess metallic Al, (ii) deposition of <3 Å of Al by atomic layer deposition, and (iii) thin-film deposition of Al by electron-beam evaporation. The surface structure, work function and electron affinity were investigated after annealing at temperatures of 300°C, 600°C and 800°C. Except for loss of excess O upon first heating, the Al+O surfaces remained stable up to 800°C. The electron affinity values were generally between 0.0 and -1.0 eV, and the work functions were generally 4.5 ± 0.5 eV, depending upon the deposition method, coverage and annealing temperature. The values are in broad agreement with those predicted by computer simulations of Al+O (sub)monolayers on a diamond surface.
Original languageEnglish
Article number2100027
Number of pages13
Journalphysica status solidi (b)
Volume258
Issue number7
Early online date30 Mar 2021
DOIs
Publication statusPublished - 1 Jul 2021

Bibliographical note

Funding Information:
M.C.J. thanks the Engineering and Physical Sciences Research Council (EPSRC) for funding under grant code EP/L016648/1 as part of the Functional Nanomaterials CDT. The authors acknowledge the Bristol NanoESCA Facility (funded by EPSRC Strategic Equipment Grants EP/K035746/1 and EP/M000605/1). The ALD work was developed within the scope of the project CICECO‐Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES.

Publisher Copyright:
© 2021 The Authors. Physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH

Keywords

  • Diamond films
  • thermionic emission
  • negative electron affinity
  • Aluminium

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