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Natural Oxidation of thin Fe Films on V Buffer Layer

100%

Dawczak-Dębicki H., Marczyńska A., Rogowska A., Wachowiak M., Nowicki M., Pacanowski S., Jabłoński B., Kowalski W., Grembowski J., Czajka R., Smardz L.

Acta Physica Polonica A

2017

vol. 132

issue 4

1272-1276

We have studied oxidation kinetics of Fe thin film under atmospheric conditions using the fact that metallic iron is a ferromagnet but ultrathin natural iron oxides are approximately nonmagnetic at room temperature. As a consequence, oxidation is associated with a loss in total Fe magnetic moment. Results show that the sample with an initial Fe thickness equal to 10 nm oxidize relatively fast (time constant τ=0.05 day), whereby a constant amount of 2.5 nm of metal is transformed into oxides. For lower iron initial thickness (d_{i}=4 nm) the time constant for oxidation significantly increases reaching a value of 2 days. Furthermore, X-ray photoelectron spectroscopy studies performed after 144 days of oxidation revealed formation of hematite (α-Fe₂O₃) thin film on the metallic rest of iron.

Comparison of Pure and Doped TiO₂ Thin Films Prepared by Sol-Gel Spin-Coating Method

52%

Çiçek Bezir N., Evcin A., Kayali R., Özen M., Balyaci G.

Acta Physica Polonica A

2017

vol. 132

issue 3

620-624

In this study, using spin-coating sol-gel method we fabricated TiO₂ thin films, doped with different concentrations (1, 2, and 3 mole %) of Ce, Dy, and Eu. Characterization of the prepared samples was performed by means of the X-ray diffraction, scanning electron microscopy, ultraviolet visible absorption, and differential thermal and thermo gravimetric analysis. X-ray diffraction measurements have shown that in Eu and Dy-doped samples crystal structure consists of mixed rutile and the dominant anatase phases, however the Ce doped samples consist of anatase phase only. Scanning electron microscopy images have revealed that while average thin film thickness of the Dy-doped samples decreases with increasing concentration of Dy, the average film thicknesses of samples doped with Ce and Eu increases with increasing concentrations of these dopants. Ultraviolet visible absorption spectroscopy measurements have shown that while absorbances of the samples doped by 1 and 2 mole % of the dopants have nearly similar properties, these properties differ from each other for 3 mole % of the dopants. Finally, differential thermal and thermo gravimetric analyses have shown that the chemical reactions and weight losses of the samples have occurred at the expected temperatures.

High-quality MBE growth of AlχGa1-χ As-based THz quantum cascade lasers

52%

Roch T., Andrews A., Fasching G., Benz A., Schrenk W., Unterrainer K., Strasser G.

Open Physics

2007

vol. 5

issue 2

244-251

High-quality GaAs-based quantum cascade laser (QCL) structures for the terahertz (THz) emission have been grown by solid source molecular-beam epitaxy. Ex-situ high-resolution x-ray diffraction shows that layer thickness and its control is the most critical growth aspect and that the lasing potential of the structure can be determined by the thickness accuracy of the layers. For our samples, the thickness tolerance for working lasing structures emitting approximately 100 μm was determined to be minimally above 1% for a 15 μm active region which was composed of 54.6 nm cascade cells. Increasing interface roughness adversely affects the lasing threshold and power.

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2 Acta Physica Polonica A

1 Open Physics

2 2017

1 2007

1 Andrews A.

1 Balyaci G.

1 Benz A.

1 Czajka R.

1 Dawczak-Dębicki H.

1 Evcin A.

1 Fasching G.

1 Grembowski J.

1 Jabłoński B.

1 Kayali R.

1 Kowalski W.

1 Marczyńska A.

1 Nowicki M.

1 Pacanowski S.

1 Roch T.

1 Rogowska A.

1 Schrenk W.

1 Smardz L.

1 Strasser G.

1 Unterrainer K.

1 Wachowiak M.

1 Çiçek Bezir N.

1 Özen M.

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Natural Oxidation of thin Fe Films on V Buffer Layer

Comparison of Pure and Doped TiO₂ Thin Films Prepared by Sol-Gel Spin-Coating Method

High-quality MBE growth of AlχGa1-χ As-based THz quantum cascade lasers