Temperature-and hydrogen-induced changes in the optical properties of Pd capped V thin films
2012 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 86, no 6, 065702- p.Article in journal (Refereed) Published
Optical properties of V thin films deposited on MgO substrates have been obtained from spectrophotometric measurements. The V films were coated with a thin Pd layer to protect them from oxidation and to favor absorption of atomic hydrogen. Electrical resistance was recorded while hydrogen pressure was increased slowly up to 750mbar keeping the temperature constant. Simultaneously, visible and near-infrared transmittance spectra of this Pd/V/MgO system were measured. The spectra were numerically inverted to obtain the spectral behavior of the Pd and V dielectric functions at 22 and 140 degrees C. Hydrogen concentrations were first determined from the combined effect of hydrogen content on the electrical resistance and on the optical direct transmission of the system. Then, determination of these concentrations was improved using retrieved values of the absorption coefficients of the hydrides and taking into account the structural change of V and the volumetric expansion of Pd. Good agreement is established when considering qualitative correlations between spectral features of the optimized PdHy and VHx dielectric functions and band structure calculations and densities of states for these two transition metal hydrides.
Place, publisher, year, edition, pages
2012. Vol. 86, no 6, 065702- p.
IdentifiersURN: urn:nbn:se:uu:diva-191794DOI: 10.1088/0031-8949/86/06/065702ISI: 000312216200022OAI: oai:DiVA.org:uu-191794DiVA: diva2:587506