Studies of the oxidation of iron by water vapour using X-ray photoelectron spectroscopy and QUASES™

Grosvenor, Andrew P.; Kobe, Brad; McIntyre, N. S.

doi:10.1016/j.susc.2004.08.035

Cited by 206 publications

(192 citation statements)

References 25 publications

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“…The presence of O 2− , OH − and H 2 O species is commonly observed in iron (oxy)hydroxides. [12,13] The general observed trend in the O(1s) spectra (Fig. 2) is an increase of the oxide component and a decrease in the hydroxyl and carbonate components with increasing x values.…”

Section: Xps Spectra Of Grs Of Various Compositionmentioning

confidence: 78%

XPS study of Fe(II)Fe(III) (oxy)hydroxycarbonate green rust compounds

Mullet

Khare

Ruby

2008

Surface & Interface Analysis

164

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Section: Xps Spectra Of Grs Of Various Compositionmentioning

confidence: 78%

XPS study of Fe(II)Fe(III) (oxy)hydroxycarbonate green rust compounds

Mullet

Khare

Ruby

2008

Surface & Interface Analysis

164

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“…Since no SiO 2 is observed in the Si2p core level of the as-grafted state, the peak at a binding energy of 532.4 eV is attributed to adventitious adsorbed OH species. 72 After ageing, the O1s peak maximum shifts to higher binding energy; the difference spectrum (circles in Fig. 2(b)) reveals an increase of the low BE component (shoulder at 532.1 eV) and a new component at 533.0 eV, which is attributed to both interface oxide (SiO 2 ) 73,74 and possibly water molecules, 72,75 which can be more strongly adsorbed than the dioxygen molecule.…”

Section: A Surface Oxidationmentioning

confidence: 98%

“…72 After ageing, the O1s peak maximum shifts to higher binding energy; the difference spectrum (circles in Fig. 2(b)) reveals an increase of the low BE component (shoulder at 532.1 eV) and a new component at 533.0 eV, which is attributed to both interface oxide (SiO 2 ) 73,74 and possibly water molecules, 72,75 which can be more strongly adsorbed than the dioxygen molecule. The total O1s signal intensity is larger than the amount expected from a SiO 2 stoichiometry for the interfacial oxide alone, by a factor of 1.7; neglecting the attenuation by the molecular layer, the amount of adventitious adsorbed OH and H 2 O molecules is thus comparable to the surface density of oxidized Si atoms.…”

Section: A Surface Oxidationmentioning

confidence: 98%

Barrier height distribution and dipolar relaxation in metal-insulator-semiconductor junctions with molecular insulator: Ageing effects

Fadjie-Djomkam

Ababou‐Girard

Godet

2012

Journal of Applied Physics

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To cite this version:Alain-Bruno Fadjie-Djomkam, Soraya Ababou-Girard, Christian Godet. Barrier height distribution and dipolar relaxation in metal-insulator-semiconductor junctions with molecular insulator: Ageing effects. Journal of Applied Physics, American Institute of Physics, 2012, 112, pp.113701-1-113701-11 Related ArticlesAtomic layer deposition of Al2O3 on GaSb using in situ hydrogen plasma exposure Appl. Phys. Lett. 101, 231601 (2012) Defect induced mobility enhancement: Gadolinium oxide (100) on Si(100) Appl. Phys. Lett. 101, 222903 (2012) Band alignment in Ge/GeOx/HfO2/TiO2 heterojunctions as measured by hard x-ray photoelectron spectroscopy Appl. Phys. Lett. 101, 222110 (2012) Electronic properties at the oxide interface with silicon and germanium through x-ray induced oxide charging Appl. Phys. Lett. 101, 211606 (2012) A computational study of graphene silicon contact J. Appl. Phys. 112, 104502 (2012) Additional information on J. Appl. Phys. Electrical transport through molecular monolayers being very sensitive to disorder effects, admittance and current density characteristics of Hg//C 12 H 25 -n Si junctions incorporating covalently bonded n-alkyl molecular layers, were investigated at low temperature (150-300 K), in the as-grafted state and after ageing at the ambient. This comparison reveals local oxidation effects both at the submicron scale in the effective barrier height distribution and at the molecular scale in the dipolar relaxation. In the bias range dominated by thermionic emission and modified by the tunnel barrier (TB) attenuation, expðÀb 0 d T Þ, where d T is the thickness of the molecular tunnel barrier and b 0 is the inverse attenuation length at zero applied bias, some excess current is attributed to a distribution of low barrier height patches.Complementary methods are used to analyze the current density J(V, T) characteristics of metal-insulator-semiconductor tunnel diodes. Assuming a Gaussian distribution of barrier heights centered at qU B provides an analytical expression of the effective barrier height, qU EFF ðTÞ ¼ qU B þ ðkTÞb 0 d T À ðqdUÞ 2 =2kT; this allows fitting of the distribution standard deviation dU and tunnel parameter ðb 0 d T Þ over a wide temperature range. In a more realistic modeling including the voltage dependence of barrier height and circular patch area, the so-called "pinch-off" effect is described by a distribution of parameter c ¼ 3ðD P R 2 P =4Þ 1=3 , which combines interface potential modulation and patch area variations. An arbitrary distribution of c values, fitted to low-temperature J(V) data, is equally well described by Gaussian or exponential functions. Ageing in air also increases the interface oxidation of Si substrate and affects the density of localized states near mid gap, which typically rises to the high 10 11 eV À1 cm À2 range, as compared with D S < 10 11 eV À1 cm À2 in the as-grafted state. The bias-independent relaxation observed near 1 kHz at low temperature may be attributed either to dipoles in the alkyl chain in...

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“…As one of our branching-ratio hypotheses involved the donation of hydrogen from surface hydroxyl species to form CHCl 3 , we followed the changes in the O 1s spectrum, which allows quantification of the oxide, hydroxyl, and adsorbed H 2 O concentrations at the surface of the nanoparticles (e.g., Grosvenor et al, 2004). We collected spectra for two sets of samples, one set that had been pre-exposed to H 2 O for various periods, and a second set that had been reacted for a few hours with aqueous CCl 4 after pre-exposure to H 2 O.…”

Section: Results-taskmentioning

confidence: 99%