Surface‐related investigations to characterize different preparation techniques of Sb‐doped SnO<sub>2</sub> powders

Szczuko, D.; Werner, J.; Behr, G.; Oswald, Steffen; Wetzig, K.

doi:10.1002/sia.1099

Cited by 24 publications

(32 citation statements)

References 26 publications

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“…In previous work [17,18,19] the dependence of the surface and bulk concentrations in Sb-, In-, Nb-doped SnO 2 powders on the method of preparation and the annealing conditions was studied. The enrichment of the doping element at the surface was revealed by X-ray photoelectron spectroscopy (XPS).…”

Section: Introductionmentioning

confidence: 99%

Specific properties of fine SnO 2 powders connected with surface segregation

Oswald

Behr

Dobler

et al. 2004

Analytical and Bioanalytical Chemistry

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The effect of surface segregation in Sb- and In-doped SnO2 fine-grained powders has been analyzed in comparison with single-crystalline samples. The kinetics and thermodynamics of the Sb and In segregation processes were studied as a function of annealing temperature by X-ray photoelectron spectroscopy (XPS) after annealing in an oxygen-containing atmosphere. Significant differences between diffusion and segregation were revealed for doped powders and single crystals, obviously because of simultaneous diffusion and particle-growth processes proceeding during annealing of powders. For doped single crystals the thermodynamic equilibrium is approached after 24 h annealing above 850 degrees C and at 1000 degrees C for Sb and In, respectively. Higher effective activation energies of diffusion are observed for doped powders and the thermodynamic equilibrium is not achieved under technologically relevant annealing conditions. On the basis of dopant profile measurements anomalies in the electrical resistivity at 300 degrees C of Sb-doped SnO2 powders annealed at 700 and 900 degrees C were attributed to an Sb-depleted zone formed beneath the segregated surface during the kinetic regime. To achieve optimum resistivity behavior for commercial application, inhomogeneous doping of powders must be avoided by appropriate preparation steps.

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Section: Introductionmentioning

confidence: 99%

Specific properties of fine SnO 2 powders connected with surface segregation

Oswald

Behr

Dobler

et al. 2004

Analytical and Bioanalytical Chemistry

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“…Therefore, it is concluded that the earlier described changes of the electrical properties caused by increasing bulk doping are in this case the main reason for changes of the AP. In fact, the calculated [14,15] bulk doping concentrations are increasing despite of the observed segregation in the same way. The changes of the AP, which occur due to the formation of a surface layer, are small in comparison with these bulk influences.…”

Section: Resultsmentioning

confidence: 64%

“…About 70% of the total amount of the dopant In and 50% of Sb remains in the crystal lattice of SnO 2 . The content of Nb in the bulk is still lower [14,15]. Therefore the Nb doped samples have higher resistivity than Sb doped ones.…”

Section: Resultsmentioning

confidence: 98%

“…In order to control the electrical and optical properties dopants such as antimony, indium, fluorine, molybdenum or niobium were added [10][11][12][13]. The properties depend not only on the doping element, but also on the oxidation state and the doping concentration [14,15]. One method for characterisation of doped tin oxides is X-ray photoelectron spectroscopy (XPS).…”

Section: Introductionmentioning

confidence: 99%

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Changes of Auger parameter in doped SnO₂ powders

Dobler¹,

Oswald²,

Behr³

et al. 2003

Cryst. Res. Technol.

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Doped SnO2 powders were studied using X‐ray photoelectron spectroscopy (XPS). The Auger parameters (AP) for Sn and different doping elements were determined. A dependence of the Auger parameter on the doping element and doping concentration was observed. The detected shift could be correlated with the electrical properties of the studied samples as well as with the formation of a second phase and a segregation layer at the surface. Bulk doping with elements having a valency greater than 4 (Sb), leads to an increase of the electron density connected with a decrease of resistivity. In this case we can observe the shift of the AP to higher values. This means that the relaxation of the electron holes is energetically more favourable for Sb doped than for pure tin oxide. On the other side, doping with elements the valency of which is less than 4 (In) on tin sites leads to a decrease in electron density and causes an increase of resistivity of the material. We observe in this case a shift of the AP to lower values due to lower relaxation energy. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…5). This shift is connected with the change in the oxidation state of antimony, which in depends on doping concentration [15,25,26,27]. For low doping concentrations Sb 5+ is dominant.…”

Section: Methodsmentioning

confidence: 99%

Calibration of XPS - energy scale for determination of the oxidation states of doping elements in SnO 2 powders

Dobler

Oswald

Wetzig

2002

Analytical and Bioanalytical Chemistry

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X-ray photoelectron spectroscopy (XPS) has been used to investigate the oxidation states of doping elements in doped SnO(2) powders. Because of low conductivity, however, charging and resulting peak shift is observed. To obtain the real peak position a suitable reference peak must be found in the XPS spectrum. In this study both internal (Sn3d(5/2) peak) and external references (Au4f(7/2) and C1 s) were examined. When external references were used a shift of all the peaks studied was observed; the extent of this depended on the doping element and the doping concentration. By doping with an element of valence >4 (Nb and Sb) we obtained peaks at binding energy (BE); doping with a trivalent element (In) led to peaks at values of the BE. This peak shift is connected with changes of Fermi level. In contrast, by using Sn3d(5/2) as reference we obtained results which enabled, for example, observation of the dependence of changes of the oxidation state of Sb on doping concentration.

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Surface‐related investigations to characterize different preparation techniques of Sb‐doped SnO₂ powders

Cited by 24 publications

References 26 publications

Specific properties of fine SnO 2 powders connected with surface segregation

Specific properties of fine SnO 2 powders connected with surface segregation

Changes of Auger parameter in doped SnO₂ powders

Calibration of XPS - energy scale for determination of the oxidation states of doping elements in SnO 2 powders

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Surface‐related investigations to characterize different preparation techniques of Sb‐doped SnO2 powders

Cited by 24 publications

References 26 publications

Specific properties of fine SnO 2 powders connected with surface segregation

Specific properties of fine SnO 2 powders connected with surface segregation

Changes of Auger parameter in doped SnO2 powders

Calibration of XPS - energy scale for determination of the oxidation states of doping elements in SnO 2 powders

Contact Info

Product

Resources

About

Surface‐related investigations to characterize different preparation techniques of Sb‐doped SnO₂ powders

Changes of Auger parameter in doped SnO₂ powders