Kinetic modelling of hydrogen ad/absorption in thin films of hydrogen sensitive field effect devices: Observation of large hydrogen induced dipoles at the Pd/SiO2 interface
1995 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, ISSN 0021-8979, Vol. 78, 988- p.Article in journal (Refereed) Published
A kinetic modeling of the hydrogen interaction with a Pd‐SiO2‐Si (Pd‐MOS) device is reported. The model is fitted to a number of experimental results, mainly from mass spectrometric desorption measurements. The new results verify an older description of the energetics of hydrogen adsorption states at the Pd/SiO2 interface in the sense that the adsorption may be described by a so‐called Temkin isotherm; however, several new findings have to be incorporated into the model in order to obtain a consistent picture. The initial heat of adsorption at the interface is around 0.8 eV/hydrogen atom. The number of adsorption sites at the interface is considerably smaller than at the surface, 6×1017 m−2 versus 1.5×1019 m−2. Furthermore, the interface hydrogen atoms are strongly polarized. An average value of 2 Debye is obtained. It is the large hydrogen polarization at the Pd/SiO2 interface and not a large concentration of adsorbed hydrogen atoms per se which accounts for the very high sensitivity of a Pd‐MOS device as hydrogen sensor
Place, publisher, year, edition, pages
1995. Vol. 78, 988- p.
IdentifiersURN: urn:nbn:se:liu:diva-67339DOI: 10.1063/1.360293OAI: oai:DiVA.org:liu-67339DiVA: diva2:409454