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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

PVT-Grown Single Crystals of Cd_{1-x}Zn_{x}Te (x ≤ 0.25) and ZnTe as Substrates for Epitaxy

100%

Mycielski A., Szadkowski A., Łusakowska E., Kowalczyk L., Domagała J., Bąk-Misiuk J., Wilamowski Z., Witkowska B.

Acta Physica Polonica A

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1998

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vol. 94

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issue 3

441-445

EN

The process of growth of single crystals of Cd_{1-x}Zn_{x}Te (x ≤ 0.25) and ZnTe by physical vapour transport has been optimized and the twin-free single crystals with a very good crystal structure and low density of dislocations are grown as substrates for MBE and other techniques of epitaxy. Characterization of the crystals is described.

3

Influence of AlN Buffer Layer Deposition Temperature οn Properties of GaN HVPE Layers

80%

Prażmowska J., Korbutowicz R., Wośko M., Paszkiewicz R., Kovač J., Srnanek R., Tłaczała M.

Acta Physica Polonica A

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2009

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vol. 116

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issue S

S-123-S-125

EN

Gallium nitride layers were deposited on AlN and double layer (AlN/AlGaN) buffers grown at various temperatures on Al_{2}O_{3}. Stress in layers was evaluated based on the Raman scattering and photoluminescence measurements. The obtained values were less than 1 GPa.

4

Formation of Uniform Germanium Islands on Silicon Substrate Using Nickel as Catalyst by Thermal Evaporation Method

80%

Jumidali M., Hashim M., Abdul Aziz A., Abd Rahim A.

Acta Physica Polonica A

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2015

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vol. 127

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issue 4

1068-1071

EN

Uniform germanium islands (GIs) were grown on Si (100) using a nickel layer as catalyst through the physical vapor deposition of germanium (Ge) powder at 1000°C at different deposition times. Prior to the deposition of Ge layer, nickel (Ni) catalyst was deposited on silicon substrates via radio frequency magnetron sputtering technique. Scanning electron microscopy results showed that the increase in deposition time resulted in a variation in surface morphology. Energy dispersive X-ray spectrometer analysis found that the GI samples composed of Ni element indicating the role of Ni in uniform Ge islands formation. The X-ray diffraction pattern spectra revealed that the GIs exhibited a Ge cubic structure and the intensity of Ge peaks varies with deposition time. In-plane strain indicated that the strain caused by the substrate is tensile and changed to compressive strain at the longer deposition time. The Raman spectra exhibited a red shift in the Ge-Ge peak, compared with the bulk Ge, as a result of compressive strain of the GIs. Fourier transform infrared spectrum analysis also indicated that the optical band gap Eg values of GIs can be varied by deposition time.

5

Stimulated Emission in Zn(Se,S) Single Crystals

80%

Kowalczyk L., Mycielski A., Szadkowski A., Testelin C., Rigaux C., Menant M.

Acta Physica Polonica A

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1997

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vol. 92

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issue 5

871-874

EN

Two different types of optically pumped stimulated emission were observed at 1.8 K in the high quality Zn(Se,S) crystals grown by low temperature physical vapour transport. One type, occurring at moderate excitation levels, is ascribed to the recombination of excitons localized because of chemical disorder in the two-anion mixed crystal. The other type, occurring at high excitation levels, is related to the inelastic exciton-exciton scattering.

6

Study of the Thermoluminescence of CVD Diamond

80%

Karczmarska A., Mitura-Nowak M., Nowak T., Marszałek M.

Acta Physica Polonica A

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2012

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vol. 121

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issue 2

510-513

EN

This work reports some thermoluminescent properties of chemical vapour deposition diamond film grown by 5 kW microwave assisted plasma chemical vapour deposition. The 2" diamond sample with the thickness of 32 μm was exposed to gamma radiation in the dose range 0.6-55 Gy. The thermoluminescent glow curve of diamond sample displayed a peak with the maximum centered at 240°C. The linearity of the detector response in the range of 10-55 Gy was observed. The bleaching effect, seen as fading of the thermoluminescent signal when the device was exposed to light in the visible range, was also noticed. Two-dimensional dose distribution was measured using 2D thermoluminescent reader equipped with a sensitive 640 × 480 pixels charge coupled device camera. The surface morphology of the diamond film was observed with scanning electron microscope and atomic force microscope. The grain size was estimated as about 15 μm. The Raman spectroscopy was used to characterize phase purity. The width and position of the diamond Raman band around 1332 cm^{-1} indicated that the coating is crystalline and of good quality. It is concluded that good quality chemical vapour deposition diamond coating could be promising material for thermoluminescent dosimetry.

7

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

80%

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.

8

Experimental and Theoretical Analysis οf PbTe-CdTe Solid Solution Grown by Physical Vapour Transport Method

70%

Szot M., Szczerbakow A., Dybko K., Kowalczyk L., Smajek E., Domukhovski V., Łusakowska E., Dziawa P., Mycielski A., Story T., Bukała M., Galicka M., Sankowski P., Buczko R., Kacman P.

Acta Physica Polonica A

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2009

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vol. 116

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issue 5

959-961

EN

Bulk monocrystals of Pb_{1-x}Cd_{x}Te, with the Cd content x up to 0.11, were grown by physical vapour transport method. The structural, electrical and optical properties of these ternary crystals were studied experimentally and theoretically. All investigated samples exhibit rock-salt structure and high crystal quality, which was confirmed by X-ray rocking curve width parameter of about 100 arcsec. The decrease of the lattice parameter with increasing Cd content x was found experimentally, in agreement with ab initio calculations. The band structures of Pb_{1-x}Cd_{x}Te mixed crystals for x values up to 0.2 were calculated using tight binding approach. The calculated band gap in the L-point increases with the Cd content in qualitative agreement with photoluminescence measurements in the infrared. For all studied Pb_{1-x}Cd_{x}Te samples, the Hall effect and electrical conductivity measurements, performed in the temperature range from 4 to 300 K, revealed p-type conductivity.

9

Electrical Characterization of Al/Ta_2O_5/Al Structures Grown by Electron Beam Deposition

70%

Yahia I., Farag A.

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vol. 125

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issue 5

1191-1196

EN

We report study of current density-voltage (J-V) and capacitance-voltage (C-V) characteristics of Al/Ta_2O_5/Al metal-insulator-metal structures prepared by electron beam deposition. At low bias voltages the J-V characteristics of Al/Ta_2O_5/Al structures show ohmic conduction. At higher voltages the conductivity becomes limited by space charge. The space charge limited conductivity is due to carrier trap centers located within the energy gap of Ta_2O_5. The distribution of the trap appears to be exponential above the valence band. Basing on the comparison of the measured temperature dependences of the current density with the theoretical model one can determine important material parameters, such as the trap density. The density of states at the Fermi level N(E_{F}) for the Ta_2O_5 film is found to be 2.75 × 10^{19} eV^{-1} cm^{-3}. The capacitance-voltage-temperature (C-V-T) characteristics of Al/Ta_2O_5/Al structures were carried out in the bias range -5 to +5 V and at temperatures from 300 to 550 K. The capacitance of Al/Ta_2O_5/Al structures increases with the increasing temperature.

10

Sb Layers on p-GaN: UPS, XPS and LEED Study

61%

Grodzicki M., Mazur P., Pers J., Zuber S., Ciszewski A.

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vol. 126

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issue 5

1128-1130

EN

The electronic structure of p-type GaN(0001) surfaces and its modification by antimony adsorption, and properties of Sb/GaN(0001) interface, are presented in this report. The studies were carried out in situ by ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and low-energy electron diffraction. Thin Sb layers were deposited under ultrahigh vacuum conditions onto the substrate at room temperature. Electron affinity of clean p-GaN surface amounted to 3.0 eV. A small amount of Sb on GaN(0001) surface reduced the electron affinity to 1.9 eV. The work function of the Sb layer was equal to 4.4 eV. For the Schottky barrier height of the Sb/GaN interface, the value of 2.50 eV was obtained.

11

AFM/STM Modification of Thin Sb Films on 6H-SiC(0001)

61%

Mazur P., Zuber S., Grodzicki M., Ciszewski A.

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vol. 126

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issue 5

1131-1133

EN

Atomic force microscopy and scanning tunneling microscopy have been used for nanometer scale modifications of Sb films deposited on 6H-SiC(0001) surface. The films are grown in situ by vapor deposition under ultrahigh vacuum. The growth follows the Volmer-Weber mode. Ultrathin (up to 3 nm on average) Sb films which consist of no coalesced islands can be modified by moving the island over the substrate surface by the AFM tip. Thicker films, which are firmer due to the coalescence, can be modified by the field and/or current produced by STM tip. Final result of the modifications is adsorbate free 6H-SiC(0001) surface restitution over the modified area.

12

Substrates Grown from the Vapor for ZnO Homoepitaxy

61%

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.

13

Structural Characterization of La_{1-x}Sr_xCoO₃ Thin Films Deposited by Pulsed Electron Deposition Method

61%

Cieniek Ł., Kopia A., Cyza A., Kowalski K., Kusiński J.

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EN

The aim of the presented research was to investigate the influence of strontium dopant on the structure and composition of La_{1-x}Sr_{x}CoO₃ (x=0, 0.1, 0.2) perovskite thin films. Pure and Sr doped LaCoO₃ thin films were grown by pulsed electron deposition technique on crystalline epi-polished Si/MgO substrates. Numerous analytical techniques (scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction) were applied to characterize their phase/chemical composition, structure and surface morphology. X-ray diffraction analysis showed the presence of pure LaCoO₃ perovskite phase in the undoped thin film. For Sr doped thin films La_{0.8}Sr_{0.2}CoO₃ (x=0.2), La_{0.9}Sr_{0.1}CoO₃ (x=0.1) small contents of La₂ O₃ and LaSrCoO₄ phases were noticed. The crystallite sizes, calculated from the Williamson-Hall plots, were about 18 nm for all analyzed films. According to scanning electron microscopy/atomic force microscopy observations, obtained thin films were free from defects and cracks. Atomic force microscopy (tapping mode) analysis revealed the differences in the shape and quantity of surface crystallites for all thin films as a result of Sr doping and different deposition parameters. Atomic force microscopy technique also allowed measurement of roughness parameters for analyzed samples. X-ray photoelectron spectroscopy analyses of chemical states of elements of thin films showed that their chemical state was stable across the film thickness and even at the interface with the MgO substrate. X-ray photoelectron spectroscopy analysis also allowed to evaluate chemical states and atomic concentration of La, Co, and Sr elements within cross-sections of deposited thin films.

Refine search results

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

PVT-Grown Single Crystals of Cd_{1-x}Zn_{x}Te (x ≤ 0.25) and ZnTe as Substrates for Epitaxy

Influence of AlN Buffer Layer Deposition Temperature οn Properties of GaN HVPE Layers

Formation of Uniform Germanium Islands on Silicon Substrate Using Nickel as Catalyst by Thermal Evaporation Method

Stimulated Emission in Zn(Se,S) Single Crystals

Study of the Thermoluminescence of CVD Diamond

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

Experimental and Theoretical Analysis οf PbTe-CdTe Solid Solution Grown by Physical Vapour Transport Method

Electrical Characterization of Al/Ta_2O_5/Al Structures Grown by Electron Beam Deposition

Sb Layers on p-GaN: UPS, XPS and LEED Study

AFM/STM Modification of Thin Sb Films on 6H-SiC(0001)

Substrates Grown from the Vapor for ZnO Homoepitaxy

Structural Characterization of La_{1-x}Sr_xCoO₃ Thin Films Deposited by Pulsed Electron Deposition Method