| 1. |
- Moldarev, Dmitrii, et al.
(författare)
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Composition of photochromic oxygen-containing yttrium hydride films
- 2018
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Ingår i: Solar Energy Materials and Solar Cells. - : ELSEVIER SCIENCE BV. - 0927-0248 .- 1879-3398. ; 177, s. 66-69
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the composition of oxygen-containing yttrium hydride (YHO) thin films was investigated. The films were prepared by reactive sputter deposition, and were found for have oxygen contents on the order of several tens of per cents. We present depth-resolved atomic composition profiles of photochromic YHO films to study the connection between composition, photochromic properties and growth parameters. Two films, deposited at different pressures, were prepared and characterized using ion beam analysis techniques, i.e. Rutherford backscattering spectrometry and elastic recoil detection analysis. We found that an increase of deposition pressure results in larger [O]/[Y] ratios, while the ratio [H]/[Y] becomes reduced. We also report a gradual oxidation of the films exposed to air as well as hydrogen release under ion bombardment.
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| 2. |
- Mongstad, Trygve, et al.
(författare)
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MgyNi1-y(H-x) thin films deposited by magnetron co-sputtering
- 2012
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 527, s. 76-83
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Tidskriftsartikel (refereegranskat)abstract
- In this work we have synthesized thin films of MgyNi1-y(H-x) metal and metal hydride with y between 0 and 1. The films are deposited by magnetron co-sputtering of metallic targets of Mg and Ni. Metallic MgyNi1-y films were deposited with pure Ar plasma while MgyNi1-yHx hydride films were deposited reactively with 30% H-2 in the Ar plasma. The depositions were done with a fixed substrate carrier, producing films with a spatial gradient in the Mg and Ni composition. The combinatorial method of co-sputtering gives an insight into the phase diagram of MgyNi1-y and MgyNi1-yHx, and allows us to investigate structural, optical and electrical properties of the resulting alloys. Our results show that reactive sputtering gives direct deposition of metal hydride films, with high purity in the case of Mg similar to 2NiH similar to 4. We have observed limited oxidation after several months of exposure to ambient conditions. MgyNi1-y and MgyNi1-yHx films might be applied for optical control in smart windows, optical sensors and as a semiconducting material for photovoltaic solar cells.
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| 3. |
- Mongstad, Trygve, et al.
(författare)
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Surface oxide on thin films of yttrium hydride studied by neutron reflectometry
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:19, s. 191604-
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Tidskriftsartikel (refereegranskat)abstract
- The applicability of standard methods for compositional analysis is limited for H-containing films. Neutron reflectometry is a powerful, non-destructive method that is especially suitable for these systems due to the large negative scattering length of H. In this work, we demonstrate how neutron reflectometry can be used to investigate thin films of yttrium hydride. Neutron reflectometry gives a strong contrast between the film and the surface oxide layer, enabling us to estimate the oxide thickness and oxygen penetration depths. A surface oxide layer of 5-10nm thickness was found for unprotected yttrium hydride films.
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| 4. |
- Mongstad, T, et al.
(författare)
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Transparent yttrium hydride thin films prepared by reactive sputtering
- 2011
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 509, s. S812-S816
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Tidskriftsartikel (refereegranskat)abstract
- Metal hydrides have earlier been suggested for utilization in solar cells. With this as a motivation we have prepared thin films of yttrium hydride by reactive magnetron sputter deposition. The resulting films are metallic for low partial pressure of hydrogen during the deposition, and black or yellow-transparent for higher partial pressure of hydrogen. Both metallic and semiconducting transparent YH(x) films have been prepared directly in situ without the need of capping layers and post-deposition hydrogenation. Optically the films are similar to what is found for YH(x) films prepared by other techniques, but the crystal structure of the transparent films differ from the well-known YH(3-eta) phase, as they have an fcc lattice instead of hcp.
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