liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Hydrogen interaction with Pt- and PdMIS devices
Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.ORCID iD: 0000-0002-0873-2877
Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
2005 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 98, no 1Article in journal (Refereed) Published
Abstract [en]

Hydrogen-sensitive Pd–SiO2–Si and Pt–SiO2–Si metal–insulator–semiconductor (MIS) devices have been studied in ultrahigh vacuum in the temperature range of 223–523 K. Adsorption/absorption of hydrogen occurs at the metal surface, in the metal bulk, and at the metal–insulator interface. The sensor signal, caused by hydrogen adsorption at the interface, shows a logarithmic dependence on the applied hydrogen pressure. The Pt-MIS device, which is fully functional at atmospheric pressures, is sensitive to changes in hydrogen pressure down to the 10−12-Torr scale. We propose that the interface adsorption follows a so-called Temkin isotherm with an interface heat of adsorption that varies with hydrogen coverage as ΔHi0(1−aθ). The initial heat of adsorption ΔHi0 is determined to 0.78 eV/hydrogen atom. The adsorption potential at the external Pt surface is found to be 0.45 eV/hydrogen atom. These values were obtained by modeling the hydrogen interaction with the MIS devices and fitting the model to a number of experimental results. Also studies of Pd-based devices were performed and compared with Pt. The hydrogen adsorption on the metal surface, previously treated as a first-order process on Pd, is shown to follow a second-order process. Qualitatively the results from the Pd- and Pt-MIS devices agree. Quantitatively there are differences. The hydrogen sensitivity of the Pt-MIS device is only approximately one-third compared to that of the Pd-MIS structure. This agrees with the result that the concentration of available hydrogen adsorption sites at the Pt–SiO2 interface is approximately 7×1017 m−2 whereas the concentrations of sites at the Pd–SiO2 interface is roughly three times larger (2×1018 m−2). An estimate of the size of the dipole moments (0.6–0.7 D) implies that the interface hydrogen atoms are strongly polarized. Differences are also observed in the microstructure of the metal films. Atomic force microscopy results show that the Pd surface reconstructs during H2–O2 exposures, while the Pt surface shows no such change at these temperatures.

Place, publisher, year, edition, pages
2005. Vol. 98, no 1
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-67403DOI: 10.1063/1.1953866OAI: oai:DiVA.org:liu-67403DiVA: diva2:409740
Available from: 2011-04-11 Created: 2011-04-11 Last updated: 2017-12-11

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Salomonsson, AnetteEriksson, MatsDannetun, Helen

Search in DiVA

By author/editor
Salomonsson, AnetteEriksson, MatsDannetun, Helen
By organisation
Applied Physics The Institute of Technology
In the same journal
Journal of Applied Physics
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 138 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf