On the increase in the electrical conductivity of MoO3 and V2O5 following ion bombardment. Studies on bombardment-enhanced conductivity-I

Naguib, Hala F.; Kelly, Roger

doi:10.1016/s0022-3697(72)80469-4

Cited by 71 publications

(28 citation statements)

References 29 publications

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“…Naguib and Kelly [9] have studied the surface modification of V 2 O 5 under Kr + bombardment with reflection electron diffraction. They have found that after an initial amorphization of the V 2 O 5 the final surface configuration is V 2 O 3 .…”

Section: Methodsmentioning

confidence: 99%

An XPS study on the surface reduction of V2O5(001) induced by Ar+ ion bombardment

et al. 2006

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The effect of the irradiation with Al Ka X-rays during an XPS measurement upon the surface vanadium oxidation state of a fresh in vacuum cleaved V 2 O 5 (0 0 1) crystal was examined. Afterwards, the surface reduction of the V 2 O 5 (0 0 1) surface under Ar + bombardment was studied. The degree of reduction of the vanadium oxide was determined by means of a combined analysis of the O1s and V2p photoelectron lines. Asymmetric line shapes were needed to fit the V 3+ 2p photolines, due to the metallic character of V 2 O 3 at ambient temperature. Under Ar + bombardment, the V 2 O 5 (0 0 1) crystal surface reduces rather fast towards the V 2 O 3 stoichiometry, after which a much slower reduction of the vanadium oxide occurs.

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Section: Methodsmentioning

confidence: 99%

An XPS study on the surface reduction of V2O5(001) induced by Ar+ ion bombardment

et al. 2006

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“…In other work bombarded VzO, was shown by electron diffraction to evolve to V,O, . 30 Subsequent bombardment by Nz+ led to extensive N incorporation such that the changes in 0 and N content very nearly balanced ( Table 2). The N 1s line shape for bombarded V,O, (Fig.…”

Section: Oxidized V (Table 1 Figs 3 and 6)mentioning

confidence: 99%

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

Bertóti

Kelly

Mohai

et al. 1992

Surface & Interface Analysis

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We have explored a new type of experiment in which the beam-induced surface changes of MgO, SiO, , A1,03, TiO,, V,O, and MgAI,04 are determined by XPS after ion bombardment at 2.5 keV with Ar+ or N,+. The initial bombardment, typically with Ar+, led to a combined surface cleaning and loss of 0. 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 Nz+ the 0 content was distinctly lower than that after Ar* impact, with the extra 0 deficiency in each case made up almost exactly by the N addition. For example, AI,O, evolved from a nominal A1202.,4 to a nominal AI2O,.zoNo.4s. The chemical state of this N was predominantly nitride-type, indicative of M-N bonds (M, metal). The observed replacement of M-0 bonds with M-N bonds is disfavoured by thermodynamics and this, combined with the already mentioned tendency for the extra 0 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 0 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.

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“…This has been observed for, e.g., V205, MOO3, and TiO2 [37,38]. In the case of TiO2 implanted with 30 keV Kr + ions (> 1017 at.…”

Section: I Electronic Conductivitymentioning

confidence: 55%

Structural, electrical and catalytic properties of ion-implanted oxides

Hassel

Burggraaf

1989

Appl. Phys. A

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Abstract. The potential application of ion implantation to modify the surfaces of ceramic materials is discussed. Changes in the chemical composition and microstructure result in important variations of the electrical and catalytic properties of oxides. 66.30, 81.40, 81.60, 61.70 Since the introduction of ion implantation as a surface modification technique, the electrical [1, 2], optical [3], magnetic [4], chemical [5], mechanical [6] and topographical [7] properties of solids have been modified. The potential use of ion implantation to modify the surfaces of ceramic materials has been discussed by Burggraaf et al. [56]. These changes in the macroscopic properties correspond to the changes in chemical composition and microstructure. In this paper this relationship is discussed for the electrical and catalytic properties of oxides, modified by ion implantation. PACS: Ion ImplantationIn the ion-implantation process, specific atoms are ionized, accelerated and mass selected [8]. Those high energetic ions (15 keV-2 MeV) penetrate in the solid and come to rest due to elastic and inelastic energy loss processes. A comprehensive treatment of the penetration of ions in solids has been given in [-9 and 10]. Depending on the process parameters the depth profile can be given different shapes, the penetration depth can be varied between some nanometers and about one micrometer and the dopant concentration in the surface can be raised to about 50 at.%. When the ion beam is properly scanned over the surface, lateral very uniform concentrations of the dopant are obtained. Due to the electrical control of the ion energy and dose, the technique is very reproducible.A major advantage of ion implantation is that a surface layer can be doped with any element, independent of its solubility in the substrate material. This means that one can produce metastable compounds, strongly supersaturated solid solutions and complex microstructures consisting of very finely dispersed precipitates with nanoscale dimensions in a matrix material. Several examples are discussed below. Microstructural Changes As-Implanted StateWhen an ion is implanted, it collides with the nuclei and electrons of the solid. In ionic oxides, only nuclear collisions result in defects [11]. Vacancies and interstitials are generated in both the anion and the cation sublattice. Interstitial loops nucleate and grow during irradiation. The lattice damage initially increases with the dose and finally saturates [11]. At that point as many defects are generated as annihilated by dynamic recovery processes in the solid. Dynamic recovery processes can be suppressed by cooling the target to low temperatures.The accumulation of defects in ion-implanted solids can result in a transition from a crystalline to an amorphous phase. This has been observed for, e.g., A1203 [12,13] [25]. The main conclusion from this model is that Fe 3 + can only exist in MgO as an isolated impurity. The fraction of Fe z + and Fe ~ is determined by the probability that, respectively, two Fe atoms and ...

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On the increase in the electrical conductivity of MoO3 and V2O5 following ion bombardment. Studies on bombardment-enhanced conductivity-I

Cited by 71 publications

References 29 publications

An XPS study on the surface reduction of V2O5(001) induced by Ar+ ion bombardment

An XPS study on the surface reduction of V2O5(001) induced by Ar+ ion bombardment

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

Structural, electrical and catalytic properties of ion-implanted oxides

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