A possible solution to the problem of compositional change with ion-bombarded oxides

Research output: Contribution to journalArticle

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Abstract

We have explored a new type of experiment in which the beam-induced surface changes of MgO, SiO2, Al2O3, TiO2, V2O5 and MgAl2O4 are determined by XPS after ion bombardment at 2.5 keV with Ar+ or N2 +. The initial bombardment, typically with Ar+, led to a combined surface cleaning and loss of O. Although the relative extents of these were difficult to establish, the result was in every case to define the composition in an N-free situation. After a subsequent bombardment with N2 + the O content was distinctly lower than that after Ar+ impact, with the extra O deficiency in each case made up almost exactly by the N addition. For example, Al2O3 evolved from a nominal Al2O2.74 to a nominal Al2O2.20N0.48. The chemical state of this N was predominantly nitride-type, indicative of M-N bonds (M, metal). The observed replacement of M-O bonds with M-N bonds is disfavoured by thermodynamics and this, combined with the already mentioned tendency for the extra O loss to be closely matched by the N addition, together constitute a strong indication that the disturbed lattice is to some extent relaxing randomly. Interestingly, however, the extent by which N replaces O increases as the energy change calculated for this replacement decreases. This confirms, in agreement with a large body of earlier work, that the changes in the oxides are to some extent also chemically guided. The similarity to ion beam mixing and to ion-beam-induced grain growth is worth noting, where again one finds a mixture of ballistic (i.e. random) and chemically guided behaviour.

Original languageEnglish
Pages (from-to)291-297
Number of pages7
JournalSurface and Interface Analysis
Volume19
Issue number1-12
DOIs
Publication statusPublished - Jun 1 1992

Fingerprint

Oxides
Ion beams
bombardment
Ions
Surface cleaning
oxides
Ion bombardment
Ballistics
ion beams
Grain growth
Nitrides
ions
X ray photoelectron spectroscopy
Metals
Thermodynamics
ballistics
cleaning
nitrides
indication
tendencies

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

A possible solution to the problem of compositional change with ion-bombarded oxides. / Bertóti, I.; Kelly, Roger; Mohai, M.; Tóth, A.

In: Surface and Interface Analysis, Vol. 19, No. 1-12, 01.06.1992, p. 291-297.

Research output: Contribution to journalArticle

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