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1

Growth of Ternary and Quaternary ZnSe Compounds with Transition Metals by Chemical Vapor Transport

100%

Janik E., Grasza K., Mycielski A., Bąk-Misiuk J., Kachniarz J.

Acta Physica Polonica A

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1993

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vol. 84

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issue 4

785-788

EN

Halogen transport method was applied to grow the crystals of solid solutions of ZnSe and transition metals at the temperature far below the melting point and phase transition temperature. The large crystals of ZnMnSe, ZnFeSe, ZnNiSe and ZnFeSSe were obtained. The technological parameters and shape of the quartz reactor were chosen for growth of a large crystal by self-nucleation; the transparent quartz furnace enabled the control of nucleation by visual observation. The parameters of crystal growth were determined. The crystal quality was estimated by X-ray diffraction method. The composition of crystals was determined by electron microprobe analysis and energy dispersive X-ray fluorescence analysis.

2

Magneto-Luminescence Study of Silicon-Vacancy in 6HSi

86%

Wysmołek A., Wardak K., Stępniewski R., Baranowski J., Potemski M., Tymicki E., Grasza K.

Acta Physica Polonica A

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2006

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vol. 110

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issue 3

437-442

EN

The magneto-spectroscopy studies of luminescence related to silicon-vacancy, in high quality 6H-SiC crystals grown by the seeded physical vapor transport method, are presented. The superior optical quality of these crystals allowed us to resolve a doublet structure of the 1.398 eV emission line (V_2 line), commonly assigned to the transitions involving two singlet states of the silicon-vacancy. Experiments performed in magnetic fields up to 20 T showed that each doublet constituent of the V_2 line splits into four components for the magnetic field parallel to the c-axis of the 6H-SiC crystals. This result could be hardly explained in terms of a singlet to singlet transition. The analysis of the angle-resolved luminescence experiments in high magnetic fields serves us to discuss the symmetry of the defect states responsible for the V_2-line in silicon carbide.

3

Raman Piezospectroscopy of Phonons in Bulk 6H-SiC

86%

Grodecki K., Wysmołek A., Stępniewski R., Baranowski J., Hofman W., Tymicki E., Grasza K.

Acta Physica Polonica A

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2009

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vol. 116

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issue 5

947-949

EN

Raman piezospectroscopy of high quality 6H-SiC crystals is presented. The crystals used in experiments were grown by the seeded physical vapor transport method. Uniaxial stress up to 0.9 MPa, obtained using a spring apparatus, was applied along [11-20] and [10-10] directions. It was found that the application of uniaxial stress led to different energy shifts of the observed phonon excitations in the investigated 6H-SiC crystals. The obtained pressure coefficients vary in the range 0.98-5.5 cm^{-1} GPa^{-1} for different transverse optical phonon modes. For longitudinal optic phonon modes pressure coefficients in the range 1.6-3.6 cm^{-1} GPa^{-1} were found. The data obtained could be useful in evaluation of local strain fields in SiC based structures and devices including epitaxial graphene.

4

Structural and Electrical Properties of SiC Grown by PVT Method in the Presence of the Cerium Vapor

86%

Avdonin A., Racka K., Tymicki E., Grasza K., Jakieła R., Pisarek M., Dobrowolski W.

Acta Physica Polonica A

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2013

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vol. 124

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issue 5

761-764

EN

The results of investigation of structural and electrical properties of bulk SiC crystals, which were grown by physical vapor transport method with different Ce impurity content added to the SiC source material, are presented. The gradual dosage of cerium from the SiC source and continuous presence of the cerium vapor over the SiC crystallization fronts during the crystal growth processes are confirmed. The cerium influences the overall concentration of structural defects. The increase of the concentration of both, donors and acceptors, and appearance of new shallow donors (15-32 meV) in 4H-SiC crystals are observed.

5

Substrates Grown from the Vapor for ZnO Homoepitaxy

86%

Skupiński P., Kopalko K., Łusakowska E., Domukhovski V., Jakieła R., Mycielski A., Grasza K.

Acta Physica Polonica A

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2008

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vol. 114

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issue 5

1361-1368

EN

The novel method of preparation of epi-ready ZnO substrates is demonstrated. The substrates were made of unique ZnO crystals grown by chemical vapor transport method using hydrogen as the transport agent. The effect of low-level doping (Mn, Co, Cu, and V) on the structural quality of the crystals was investigated. Atomic layer deposition was used to verify usability of the substrates for homoepitaxy. The thermal annealing prior to the atomic layer deposition process and effect of thermal annealing of the epitaxial layers was studied. The X-ray diffraction and atomic force microscopy methods were applied to study the structural quality of the ZnO layers. Detection of the dopants in the substrates by secondary ion mass spectroscopy made possible the measurement of the thickness of the layers. The obtained root mean square roughness for both the substrates and layers ranged between 0.2 nm and 5 nm, and was dependent on the sample crystallographic orientation and sequence of polishing and annealing procedures. The optimal recipe for the epi-ready substrate preparation was formulated.

6

Temperature Study of Photoluminescence from Deep CdTe/Cd_{1-x}Mn_{x}Te Quantum Wells

73%

Kutrowski M., Wojtowicz T., Karczewski G., Kopalko K., Zakrzewski A. K., Janik E., Grasza K., Łusakowska E., Kossut J.

Acta Physica Polonica A

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1995

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vol. 87

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issue 2

500-504

EN

The photoluminescence studies in CdTe/CdMnTe quantum wells are reported in the temperature range 10-300 K. The MnTe concentration in the barriers is x = 0.3, 0.5, 0.63 and 0.68. Thus the potential wells in our samples are very deep, of the order of ≈ 800 meV in the conduction band and ≈ 200 meV in the valence band in the case of the x = 0.68 sample. In spite of the large lattice mismatch (related to high x value) between the wells and the barriers the observed line widths are as narrow as 2 meV in the case of 100 Å. Clear manifestations of internal strain are observed. In particular, the temperature coefficient of the luminescence energies shows strong dependence on the width of wells.

7

(120)-Oriented CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy

73%

Kutrowski M., Karczewski G., Cywiński G., Surma M., Grasza K., Łusakowska E., Kossut J., Wojtowicz T.

Acta Physica Polonica A

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1996

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vol. 90

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issue 5

879-882

EN

We report on the MBE growth and magnetooptical studies of (120)-oriented CdTe/CdMnTe quantum well structures. The quality of structures, as evaluated by the photoluminescence line width, was as good as that of the best structures grown in ⟨100⟩ direction. No spin splitting enhancement, expected theoretically, due to the reduction of the antiferromagnetic interaction between Mn ions in CdTe/CdMnTe digital alloy quantum wells grown along ⟨120⟩ direction was observed.

8

Vertical Electron Transport through PbS-EuS Structures

59%

Wrotek S., Dybko K., Morawski A., Mąkosa A., Wosiński T., Figielski T., Tkaczyk Z., Łusakowska E., Story T., Sipatov A., Szczerbakow A., Grasza K., Wróbel J., Palosz W.

Acta Physica Polonica A

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2003

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vol. 103

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issue 6

629-635

EN

Temperature dependence of current-voltage I-V characteristics and resistivity is studied in ferromagnetic PbS-EuS semiconductor tunnel structures grown on n-PbS (100) substrates. For the structures with a single (2-4 nm thick) ferromagnetic EuS electron barrier we observe strongly non-linear I-V characteristics with an effective tunneling barrier height of 0.3-0.7 eV. The experimentally observed non-monotonic temperature dependence of the (normal to the plane of the structure) electrical resistance of these structures is discussed in terms of the electron tunneling mechanism taking into account the temperature dependent shift of the band offsets at the EuS-PbS heterointerface as well as the exchange splitting of the electronic states at the bottom of the conduction band of EuS.

9

Fabrication and Electrical Characterization of PbS-EuS Ferromagnetic Semiconductor Microstructures

59%

Wrotek S., Morawski A., Tkaczyk Z., Mąkosa A., Wosiński T., Dybko K., Łusakowska E., Story T., Sipatov A., Péecz B., Grasza K., Szczerbakow A., Wróbel J.

Acta Physica Polonica A

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2004

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vol. 105

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issue 6

615-620

EN

Current-voltage characteristics and temperature dependence of differential conductance were studied in lithographically patterned (lateral dimensions from 10 x 10 μm^2 to 100 x 100 μm^2) ferromagnetic EuS-PbS-EuS microstructures. Below the ferromagnetic transition temperature a 4% decrease in the structure conductance was observed for mutual antiferromagnetic orientation of magnetization vectors of ferromagnetic EuS layers.

10

Magnetic and Structural Properties of EuS-PbS Multilayers Grown on n-PbS (100) Substrates

59%

Chernyshova M., Łusakowska E., Domukhovski V., Grasza K., Szczerbakow A., Wrotek S., Kowalczyk L., Story T., Smits C., Swagten H., De Jonge W., Palosz W., Sipatov A., Volobuev V.

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issue 4-5

609-615

EN

Magnetic properties of semiconductor EuS(t)-PbS(d)-EuS(t) ferromagnetic trilayers (t=30÷300Å and d=7.5÷70Å) grown on n-type monocrystalline PbS (100) substrate were studied by SQUID magnetometry and ferromagnetic resonance technique yielding, in particular, the dependence of the ferromagnetic Curie temperature on the thickness of the EuS layer. Structural parameters of layers were examined by X-ray powder diffraction analysis. A high structural quality of the substrate and the multilayer was verified by the measurements of the X-ray rocking curve width indicating the values of the order of 100 arcsec and by atomic force microscopy revealing the presence on the cleft PbS surface regions practically flat in the atomic scale over the area of 1×0.1μm^2.

Refine search results

Growth of Ternary and Quaternary ZnSe Compounds with Transition Metals by Chemical Vapor Transport

Magneto-Luminescence Study of Silicon-Vacancy in 6H­Si

Raman Piezospectroscopy of Phonons in Bulk 6H-SiC

Structural and Electrical Properties of SiC Grown by PVT Method in the Presence of the Cerium Vapor

Substrates Grown from the Vapor for ZnO Homoepitaxy

Temperature Study of Photoluminescence from Deep CdTe/Cd_{1-x}Mn_{x}Te Quantum Wells

(120)-Oriented CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy

Vertical Electron Transport through PbS-EuS Structures

Fabrication and Electrical Characterization of PbS-EuS Ferromagnetic Semiconductor Microstructures

Magnetic and Structural Properties of EuS-PbS Multilayers Grown on n-PbS (100) Substrates

Magneto-Luminescence Study of Silicon-Vacancy in 6HSi