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1
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DLTS Study of Be-Doped p-Type AlGaAs/GaAs MBE Layers

100%
Szatkowski J., Płaczek-Popko E., Sierański K., Hansen O.
Acta Physica Polonica A
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1998
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vol. 94
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issue 3
565-569
EN
Deep-level transient spectroscopy method was applied to study deep hole traps in p-type Al_{0.5}Ga_{0.5}As grown on GaAs semi-insulating substrate by MBE. Five hole traps labelled by us as H0 to H4 were found. For the traps H1, H3 and H4 thermal activation energies obtained from Arrhenius plots were equal to: E_{H1}=0.15 eV, E_{H3}=0.4 eV, and E_{H4}=0.46 eV. Hole emission from the trap H2 was electric field dependent with the thermal activation energy extrapolated to zero-field equal to 0.37 eV. Capture cross-sections for the traps H1 and H4 were thermally activated with energetic barriers 0.04 eV (for H1) and 0.18 eV (for H4).
2
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Deep Levels in Cd_{0.99}Mn_{0.01}Te:Ga

100%
Szatkowski J., Płaczek-Popko E., Sierański K., Bieg B.
Acta Physica Polonica A
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1998
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vol. 94
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issue 3
575-578
EN
Two types of samples were studied. In the material with higher donor concentration four electron traps labelled by us as E1 to E4 were found. For the traps E2 and E3 energies obtained from Arrhenius plots are equal to 0.24 eV and 0.36 eV, respectively. Electric field enhanced electron emission from the levels E1 and E4 was observed and described in terms of Frenkel-Poole mechanism. Capture process from the traps E2 was found to be thermally activated with energetic barriers equal to 0.20 eV for E2.
3
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Influence of Twinning on Local Electronic Properties of ZnSe

100%
Balcerzyk M., Grinberg M., Szatkowski J.
Acta Physica Polonica A
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1992
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vol. 82
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issue 5
890-892
EN
We have obtained ZnSe single crystals by vertical Bridgman method. The surface was examined using scanning electron microscope (SEM). As usual crystals exhibited twins, which were observed on the (110) surface. On as-grown and n-type samples we observed long (of the order of millimetres) linear structures parallel to the (111) plane which correspond to the twin plane. Our observations and measurements enabled us to estimate the electronic potential as being of the order of a few volts and extending less than 1 μm in the direction perpendicular to the twin planes.
4
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Electrical Characteristics of Metal/p-type CdTe Schottky Contacts

100%
Szatkowski J., Sierański K., Kasprzak J.
Acta Physica Polonica A
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1991
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vol. 79
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issue 2-3
175-178
EN
The Schottky barrier height of Al, Mg and Ag on chemically prepared p-type surface were measured with I-V techniques. The barrier heights were found to be independent of metal used, and equal to 0.73 ± 0.02 eV.
5
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Structural Studies of Welds in Wear-Resistant Steels

100%
Bramowicz M., Kulesza S., Lewalski P., Szatkowski J.
Acta Physica Polonica A
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2016
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vol. 130
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issue 4
963-965
EN
The work presents results of the research on changes in microstructural, and mechanical properties of the structural XAR 400 wear-resistant steel caused by the welding procedure. Metallographic and microhardness studies revealed complex microstructure of the welds that turned out to vary with the distance from the weld axis: predominance of the acicular ferrite (ACF) structures in the weld itself, quasi-polygonal ferrite (QPF) crystals with precipitates of troostite (T) in the heat-affected zone, and the bainitic ferrite (BF) structures in the heat-partially-affected zone.
6
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Electrical Properties of Au/n-GaAs_{1-x}Sb_{x} Contacts

100%
Szatkowski J., Kasprzak J. F., Płaczek-Popko E., Radojewska E. B.
Acta Physica Polonica A
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1991
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vol. 79
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issue 2-3
179-182
EN
The Schottky barrier heights of Au on n-type GaAs_{1-x}Sb_{x} were measured with I-V, C-V, and photoresponse (PR) techniques. The barrier height was determined to be 0.65, 0.75 and 0.7 eV, respectively.
7
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Electrical and Optical Properties of ZnSe:Mg Crystals

100%
Szatkowski J., Firszt F., Męczyńska H., Łęgowski S.
Acta Physica Polonica A
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1993
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vol. 84
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issue 3
531-534
EN
ZnMgSe mixed crystals were obtained by the high pressure Bridgman method and by thermal diffusion of Mg metal into ZnSe crystals. Measurements of luminescence and transmission spectra show that the band-gap energy of such mixed crystals is larger than that of "pure" ZnSe. ZnMgSe crystals exhibit n-type conductivity and electrical parameters comparable with that of ZnSe. Blue-violet luminescence in the temperature range from 40 K to room temperature was observed. This feature makes this material very promising for future applications in constructing short wavelength electroluminescent devices.
8
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The Influence of Argon on the Deposition and Structure of Polycrystalline Diamond Films

100%
Benzhour K., Szatkowski J., Rozpłoch F., Stec K.
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issue 3
447-449
EN
Thin polycrystalline diamond films were deposited on prepared (100) Si substrate by hot filament chemical vapor deposition using a mixture of hydrogen, propane-butane and argon. During investigations the gas flow of argon was varied from 100 sccm to 400 sccm. Scanning electron microscopy analysis revealed that the addition of argon to the gas phase influenced the growth rate and film structure. An increase of argon concentration provokes an increase in film porosity and decrease in crystalline facetting. The quality of these films was investigated with the use of the Raman spectroscopy.
9
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Electrical Characterization of Defects in Schottky Au-CdTe:Ga Diodes

88%
Dyba P., Płaczek-Popko E., Zielony E., Gumienny Z., Szatkowski J.
Acta Physica Polonica A
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2009
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vol. 116
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issue 5
944-946
EN
Deep electron states in gallium doped CdTe have been studied by deep-level transient spectroscopy method. The Schottky Au-CdTe diodes were processed to perform the investigations. Rectifying properties of diodes have been examined by the room temperature current-voltage and capacitance-voltage measurements. Deep-level transient spectroscopy measurements performed in the range of temperatures 77-350 K yield the presence of three electron traps. The thermal activation energies and apparent capture cross-sections have been determined from related Arrhenius plots. The dominant trap of activation energy E_2 = 0.33 eV and capture cross-section σ_2 = 3 × 10^{-15} cm^2 has been assigned to the gallium related DX center present in the CdTe material.
10
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Impedance Spectroscopy of Au-CdTe:Ga Schottky Contacts

88%
Płaczek-Popko E., Trzmiel J., Gumienny Z., Wojtyna E., Szatkowski J.
Acta Physica Polonica A
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2008
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vol. 114
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issue 5
1279-1283
EN
The dielectric response of Au-CdTe gallium doped Schottky contacts was investigated by impedance spectroscopy in the frequency range from 0.2 Hz to 3 MHz, at temperatures in the range from 77 K to 300 K. Combined modulus and impedance spectroscopic plots were analyzed to study the response of the structure. The data were fitted with the simple RC circuit composed of a depletion layer capacitance in parallel with resistance and a series resistance of the bulk CdTe:Ga. The activation energy of the bulk trap obtained from the Arrhenius plot of the resistance was found to be equal to 0.08 eV, close to the value 0.09 eV obtained from the impedance-modulus spectroscopy. The trap dominant in CdTe:Ga is possibly the DX center related, as it has been observed that this is the dominant trap in the material.
11
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Non-Exponential Photoionization of the DX Centers in Gallium Doped CdTe and Cd_{0.99}Mn_{0.01}Te

88%
Trzmiel J., Płaczek-Popko E., Weron K., Szatkowski J., Wojtyna E.
Acta Physica Polonica A
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2008
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vol. 114
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issue 5
1417-1420
EN
The low temperature non-exponential transients of photoconductivity build-up in gallium doped Cd_{0.99}Mn_{0.01}Te and CdTe alloys possessing DX centers were studied. It was found that the two-exponential model commonly used to explain the persistent photoconductivity growth in semiconductors with DX centers describes properly solely the photokinetics obtained for CdTe:Ga. In the case of Cd_{0.99}Mn_{0.01}Te:Ga the stretched-exponential approach is more appropriate, for it explains the short-time power-law exhibited by the experimental data.
12
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Composition Dependence of Photoluminescence Spectra in Zn_{1-x}Mg_{x}Se Mixed Crystals

76%
Firszt F., Łęgowski S., Μęczyńska H., Szatkowski J., Paszkowicz W., Spolnik Z. M.
Acta Physica Polonica A
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1995
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vol. 88
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issue 4
711-714
EN
Ζn_{1-x}Mg_{x}Se mixed crystals with x ranging from 0 to 0.56 were obtained by high pressure Bridgman method. It has been found that a phase transition from sphalerite structure to wurtzite one occurs at x = 0.185 ± 0.03. The crystals exhibit blue-violet and yellow-green (depending on x) luminescence in the temperature range from 40 K to room temperature. An attempt has been also made to dope Ζn_{1-x}Μg_{x}Se crystals with Al. The incorporation of Al produces a strong green photoluminescence in the temperature range from 40 K to 300 K but almost completely quenches the near-band-edge emission.
13
Content available remote

Deep Level Transient Spectroscopy Studies of CdMnTe

76%
Szatkowski J., Płaczek-Popko E., Hajdusianek A., Kuźmiński S., Bieg B., Becla P.
Acta Physica Polonica A
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1995
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vol. 87
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issue 2
387-390
EN
Deep levels in Ga doped n-type CdMnTe of 1% and 5% Mn contents and In doped n-type CdMnTe of 20% Mn content were studied using deep level transient spectroscopy technique. Our deep level transient spectroscopy results show presence of several groups of different traps.
14
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Photoluminescence and Photoacoustic Investigations of Beryllium and Magnesium Containing Wide Gap II-VI Mixed Crystals

76%
Firszt F., Łęgowski S., Męczyńska H., Sekulska B., Szatkowski J., Zakrzewski J., Paszkowicz W.
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vol. 95
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issue 6
991-996
EN
Zn_{1-x}Be_{x}Se, Cd_{1-x}Mg_{x}Se and Zn_{1-x-y}Be_{x}Mg_{y}Se mixed crystals grown from the melt with different concentrations of Be and Mg have been characterized by photoluminescence and photoacoustic methods. An increase in band gap energy with increasing Be and Mg contents was observed. The photoacoustic spectroscopy was also employed for evaluation of thermal diffusivity of mixed Zn_{1-x}Be_{x}Se crystals with different beryllium contents.
15
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Capacitance-Voltage Studies of Ti/p-ZnTe Schottky Barrier Structures Containing CdTe Quantum Dots

76%
Placzek-Popko E., Szatkowski J., Zielony E., Gumienny Z., Dobaczewski L., Karczewski G.
Acta Physica Polonica A
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2011
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vol. 119
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issue 5
621-623
EN
In this paper the electronic states of self-organized CdTe quantum dots embedded in ZnTe matrix are studied by means of capacitance-voltage (C-V) characteristics within the temperature range of 180-300 K. A reference diode of the same layer structure but without quantum dots is studied also for comparison. The C-V characteristics measured for the reference diode exhibit bulk behaviour in contrast to the quantum dots sample for which a characteristic step corresponding to discharging of quantum dots is clearly visible within broad range of temperatures. A quasistatic model based on the self-consistent solution of the Poisson equations is used to simulate the capacitance. By comparison the calculated C-V curve with experimental curve the apparent thermal activation energy for hole emission from the quantum dots to the ZnTe matrix is found to be equal to (0.12 ± 0.03) eV.
16
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Photoacoustic Investigation of Absorption Edge of Cd_{1-x}Mg_{x}Se Mixed Crystals

76%
Firszt F., Łęgowski S., Męczyńska H., Sekulska B., Szatkowski J., Zakrzewski J., Paszkowicz W.
Acta Physica Polonica A
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1997
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vol. 92
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issue 4
749-752
EN
The Cd_{1-x}Mg_{x}Se crystals were grown by modified Bridgman method for x ranging from 0 to 0.44. The photoacoustic spectroscopy was employed for evaluation of the band gaps of series Cd_{1-x}Mg_{x}Se mixed crystals with different composition. The photoacoustic spectra were measured at 300 K and 90 K using continuous wave excitation in the range from 400 nm to 800 nm. The increase in the band-gap energy with increasing Mg content is observed. The photoacoustic results are compared with photoluminescence and transmission spectra.
17
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Optical and Structural Properties of Zn_{1-x}Be_{x}Se Mixed Crystals

64%
Firszt F., Łęgowski S., Męczyńska H., Szatkowski J., Zakrzewski J., Paszkowicz W., Domagała J., Marczak M.
Acta Physica Polonica A
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1998
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vol. 94
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issue 2
309-312
EN
Optical and structural properties of Zn_{1-x}Be_{x}Se bulk crystals in the range of composition 0 ≤ x ≤ 0.41 have been studied. These crystals were grown by Bridgman method under an argon overpressure. Transmission, absorption, photoluminescence and photoacoustic spectra as a function of composition were investigated. It has been found that the crystal structure is of sphalerite type. The crystal quality increases when the crystallization process of the same boule is performed more than once. In the investigated composition range the lattice constant decreases and the energy gap increases with increasing beryllium content. From photoluminescence measurements the excitonic energy gap about 3.64 eV at 40 K was estimated for the highest obtained Be concentration (x=0.41).
18
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Positron Annihilation Characteristics in Zn_{1-x}Mg_{x}Se Mixed Crystals

64%
Firszt F., Szatkowski J., Męczyńska H., Łęgowski S., Saarinen K., Hautojarvi P., Plazaola A., Reniewicz H., Dobrzyński L., Chabik S.
Acta Physica Polonica A
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1998
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vol. 94
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issue 2
300-304
EN
Positron annihilation characteristics as a function of composition and annealing in zinc vapour were measured and compared with photoluminescence spectra for Zn_{1-x}Mg_{x}Se mixed crystals with 0 ≤ x ≤ 0.6. The positron annihilation data show that there is a substantial number of divacancies present in the system under study. The concentration of such defects is reduced at least by the factor of two upon annealing in zinc vapour.
19
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Raman Scattering in Zn_{1-x}Mg_{x}Se Mixed Crystals

64%
Kozielski M., Szybowicz M., Firszt F., Łęgowski S., Męczyńska H., Sekulska B., Szatkowski J., Paszkowicz W.
Acta Physica Polonica A
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1996
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vol. 90
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issue 5
1040-1044
EN
This paper presents results of investigations of the Raman scattering of vibrational modes in Zn_{1-x}Mg_{x}Se crystals for the range of composition 0 < x < 0.43. The Raman polarized spectra of Zn_{1-x}Mg_{x}Se were measured at room temperature. The typical Raman spectrum shows four peaks which can be interpreted as longitudinal and transverse optical ZnSe-like and MgSe-like phonons. The ZnSe-like and MgSe-like vibrations can be described by the modified random element isodisplacement model. Results of the Raman measurements in the investigated range of composition confirm the two-mode behaviour of the optical phonons in the mixed Zn_{1-x}Mg_{x} Se crystals.
20
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Deep Levels Induced by CdTe/ZnTe Quantum Dots

64%
Zielony E., Placzek-Popko E., Roznicka A., Gumienny Z., Szatkowski J., Dyba P., Pacuski W., Kruse C., Hommel D., Guziewicz M.
Acta Physica Polonica A
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2011
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vol. 119
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issue 5
630-632
EN
The electrical properties of the CdTe/ZnTe quantum dot system have been analyzed to identify deep-level defects related with the presence of quantum dots. The capacitance-voltage (C-V) and deep level transient spectroscopy measurements were used to investigate the samples. A reference ZnTe sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the n-type GaAs substrate. The quantum dots were formed by a Zn-induced reorganization of a thin CdTe layer. The presence of quantum dot formation was confirmed by micro-photoluminescence measurements. The deep level transient spectra for both samples are complex. In order to characterize individual contributions to the deep level transient spectra the latter have been simulated by separated Gaussian components [1]. The results of the deep level transient spectroscopy measurements yield the conclusion that the same defects are present in both materials but there is an increased concentration of the defects in the quantum dot structures. No deep level associated directly with the quantum dot confinement has been identified.
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