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1

Synchrotron Photoemission Study of Ferromagnetic (Zn,Co)O Films

100%

Guziewicz E., Lukasiewicz M., Wachnicki L., Kopalko K., Dłużewski P., Jakiela R., Godlewski M.

Acta Physica Polonica A

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2011

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vol. 120

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issue 6A

A-40-A-42

EN

The electronic structure of ferromagnetic (Zn,Co)O films was investigated by resonant photoemission across the Co 3p → Co 3d photoionization threshold, e.g. using photon energy between 50 eV and 66 eV. The films were grown by atomic layer deposition at temperature between 160C and 300C and they differed in distribution and content of cobalt. The maximum of the Fano resonance was observed at photon energy 63 eV, whereas the minimum at 58 eV. The difference between energy distribution curves taken at 63 eV and the one taken at 58 eV was calculated for a series of samples. It shows that the Co 3d contribution to the valence band electronic structure of ferromagnetic (Zn,Co)O films differs significantly from that of the films which show the paramagnetic response.

2

Defect Structure of High-Temperature-Grown GaMnSb/GaSb

84%

Romanowski P., Bak-Misiuk J., Dynowska E., Domagala J., Sadowski J., Wojciechowski T., Barcz A., Jakiela R., Caliebe W.

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issue 2

341-343

EN

GaMnSb/GaSb(100) layers with embedded MnSb inclusions have been grown at 720 K using MBE technique. This paper presents the investigation of the defect structure of Ga_{1-x}Mn_{x}Sb layers with different content of manganese (up to x = 0.07). X-ray diffraction method using conventional and synchrotron radiation was applied. Dimensions and shapes of inclusions were detected by scanning electron microscopy. Depth profiles of elements were measured using secondary ion mass spectroscopy technique.

3

Investigation of Co Ions Diffusion in Gd₃Ga₅O₁₂ Single Crystals

68%

Sugak D., Syvorotka I., Yakhnevych U., Buryy O., Vakiv M., Ubizskii S., Włodarczyk D., Zhydachevskyy Y., Pieniążek A., Jakiela R., Suchocki A.

Acta Physica Polonica A

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2018

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vol. 133

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issue 4

959-964

EN

Spatial changes of properties of Gd₃Ga₅O₁₂ (GGG) single crystals caused by diffusion of cobalt ions during high-temperature annealing (1200°C, 24 h) in Co₃O₄ powder are investigated. The registration of these changes was carried out by optical spectrophotometry, microscopy and micro-Raman scattering methods. Changes in structure of near-surface layers of the crystal were investigated by X-ray diffraction technique. It was shown that the additional absorption induced by annealing is related to intra-center optical transitions in Co²⁺ ions, which occupy tetrahedral positions in the garnet structure at the distances of 250-500 μm from the crystal surface. The dependence of induced absorption with depth has got a non-monotonous character with a maximum at 400 μm. A comparison of the results obtained by different methods allows to suppose that the thermal treatment of GGG in the presence of cobalt ions leads to formation of the structurally and chemically non-uniform layer with a width about 500 μm.

4

Schottky Junctions Based on the ALD-ZnO Thin Films for Electronic Applications

68%

Krajewski T., Luka G., Smertenko P., Zakrzewski A., Dybko K., Jakiela R., Wachnicki L., Gieraltowska S., Witkowski B., Godlewski M., Guziewicz E.

Acta Physica Polonica A

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2011

|

vol. 120

|

issue 6A

A-17-A-21

EN

The ZnO-based Schottky diodes revealing a high rectification ratio may be used in many electronic devices. This paper demonstrates several approaches to obtain a ZnO-based Schottky junction with a high rectification ratio. The authors tested several methods such as: post-growth annealing of the ZnO layer, acceptor (nitrogen) doping, as well as the ZnO surface coating with a properly chosen dielectric material. The influence of these approaches on the diode's rectification ratio together with modeling based on the differential approach and thermionic emission theory are presented.

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Synchrotron Photoemission Study of Ferromagnetic (Zn,Co)O Films

Defect Structure of High-Temperature-Grown GaMnSb/GaSb

Investigation of Co Ions Diffusion in Gd₃Ga₅O₁₂ Single Crystals

Schottky Junctions Based on the ALD-ZnO Thin Films for Electronic Applications