P. Dluzewski - Academia.edu (original) (raw)
Papers by P. Dluzewski
Journal of the Korean Physical Society, 2008
We review our results on the growth of ZnTe-and CdTe-based nanowires (NWs) and on their basic str... more We review our results on the growth of ZnTe-and CdTe-based nanowires (NWs) and on their basic structural and optical properties. The nanowires were produced by using molecular beam epitaxy (MBE) with the use of a mechanism of catalytically-enhanced growth. The growth of ZnTe, CdTe, ZnMgTe and ZnMnTe nanowires was performed from elemental Zn, Cd, Mn, Mg and Te sources on the surfaces of (001)-, (110)-and (111)B-oriented GaAs substrates with Au nanocatalysts. The morphological and structural properties of the nanowires were assessed by using X-ray diffractometry, field-emission scanning electron microscopy, and high resolution transmission electron microscopy. Additional studies of the compositions of both the nanowires and the Au-rich nanocatalysts were performed with the use of energy dispersive X-ray spectroscopy. The optical properties of the NWs were assessed by using photoluminescence and Raman-scattering studies performed in both macro and micro modes. The studies revealed that binary and quaternary nanowires with average diameters from 30 to 70 nm and lengths from 1 to 2.6 µm were monocrystalline in their upper parts, their growth axis was 111 , and they grow along the [111] direction of the substrate, independent of the substrate orientation used. A Au-rich (with 20 % Ga) spherical nanocatalyst was always visible at the tip of a nanowire, thus indicating that a vapor-liquid-solid mechanism was responsible for the growth of the ZnTe-and the CdTe-based nanowires. The formation of homogeneous mixed crystal ZnMnTe and ZnMgTe nanowires was demonstrated by measurements of the variation of the lattice constant and by Raman experiments that revealed the expected shift and appearance of new phonon lines and a strong enhancement of the LO-phonon structures for an excitation close to the exciton energy of the NW materials. The photoluminescence from the internal Mn 2+ transition between crystal-field-split energy levels (4 T1 → 6 A1) was observed in the ZnMnTe nanowires.
We study an photoluminescence line of a single, self assembled CdTe quantum dot embedded in a fie... more We study an photoluminescence line of a single, self assembled CdTe quantum dot embedded in a field-effect structure. As a reverse bias is applied the line becomes broader and its intensity is decreased as a result of enhanced escape of the photocreated carriers. We account for the observed effects in a semiclassical model.
We report on the catalytically enhanced molecular beam epitaxial growth of Zn{sub 1-x}MnTe-based ... more We report on the catalytically enhanced molecular beam epitaxial growth of Zn{sub 1-x}MnTe-based nanowire structures, with manganese content up to x = 0.6, and on their basic structural and optical properties. The measurements that have been carried out confirm the incorporation of Mn{sup 2+} ions in the cation substitutional sites of ZnTe lattice.
We study the superconductor–insulator transition in Si/Nb/Si trilayers, in which the thickness of... more We study the superconductor–insulator transition in Si/Nb/Si trilayers, in which the thickness of Si is fixed at 10 nm, and the nominal thickness of Nb changes in the range between d = 20 nm down to d = 0.3 nm. The transmission electron microscopy indicates the formation of the mixed Nb–Si layer for small d. Both the thickness-induced, and the magnetic-field induced superconductor–insulator transition is observed. The crossing point of the isotherms at the critical field B c decreases with decreasing d, and it is T -independent at temperatures below 300 mK. At larger fields the weak peak in magnetoresistance appears in some of the films.
Acta Physica Polonica A - ACTA PHYS POL A, 2007
Catalytically enhanced growth of ZnMnTe diluted magnetic semiconductor nanowires by molecular bea... more Catalytically enhanced growth of ZnMnTe diluted magnetic semiconductor nanowires by molecular beam epitaxy is reported. The growth is based on the vapor-liquid-solid mechanism and was performed on (001) and (011)-oriented GaAs substrates from elemental sources. X-ray diffractometry, scanning and transmission electron microscopy, atomic force microscopy, photoluminescence spectroscopy, and Raman scattering were performed to determine the structure of nanowires, their chemical composition, and morphology. These studies revealed that the obtained ZnMnTe nanowires possess zinc-blende structure, have an average diameter of about 30 nm, typical length between 1 and 2 mum and that Mn2+ ions were incorporated into substitutional sites of the ZnTe crystal lattice.
physica status solidi (c), 2007
ABSTRACT By means of deep level transient spectroscopy (DLTS) a dislocation-related deep-level tr... more ABSTRACT By means of deep level transient spectroscopy (DLTS) a dislocation-related deep-level trap has been revealed in partially strain-relaxed InGaAs/GaAs heterostructures, grown by MOVPE. On the basis of the specific criteria containing DLTS-line shape and behaviour analysis as well as capture kinetics measurements, we were able to attribute the trap to “localized” states at the dislocation core or close to it. A direct comparison of DLTS concentration profiles and TEM results enable us to attribute the electron trap to 60° misfit dislocations lying at the heterostructure interface. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
physica status solidi (b), 2004
Investigation is carried out by high-resolution electron microscopy on threading dislocations usi... more Investigation is carried out by high-resolution electron microscopy on threading dislocations using data treatments with procedures that allow the extraction of the most likely atomic configurations. We also report In composition fluctuations inside InGaN/GaN quantum wells by coupling HRTEM, image simulation and Finite Element Modelling (FEM) of the thin foil relaxation. The results show that the indium content may be close to x = 1.0 in the clusters and this is much higher that was previously suggested by 2D FEM modelling.
Journal of Applied Physics, 2002
In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells... more In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells in metalorganic vapor phase epitaxy J. Appl. Phys. 115, 094906 (2014); 10.1063/1.4867640
Diamond and Related Materials, 2004
Films composed of Ni nanocrystals placed in an amorphous carbon matrix were investigated by photo... more Films composed of Ni nanocrystals placed in an amorphous carbon matrix were investigated by photoelectric methods. Information about the structure of Ni nanocrystals and the amorphous carbon matrix were obtained from TEM and Raman spectroscopy, respectively. The lowering of the photoelectric threshold (from 2.61 to 2.55 eV) as well as an increase of the photoelectric charge sensitivity after film cleaning with UV laser light was found.
Applied Physics Letters, 2005
ABSTRACT Formation of MnAs quantum dots in a regular ring-like distribution has been found on mol... more ABSTRACT Formation of MnAs quantum dots in a regular ring-like distribution has been found on molecular beam epitaxy grown (GaMn)As(100) surfaces after low-temperature annealing under As capping. The appearance of the dots depends on the thickness and Mn concentration in the (GaMn)As layer. With 5 at. % substitutional Mn the quantum dots showed up for layers thicker than 100 nm. For thinner layers the surfaces of the annealed samples are smooth and well ordered with 1×2 surface reconstruction, just as for as-grown (GaMn)As. The annealed surfaces are Mn rich, and are well suited for continued epitaxial growth.
GaN quantum dots (QDs) grown in semipolar (1122) AlN by plasma-assisted molecular-beam epitaxy we... more GaN quantum dots (QDs) grown in semipolar (1122) AlN by plasma-assisted molecular-beam epitaxy were studied by transmission electron microscopy (TEM) and scanning transmission electron microscopy techniques. The embedded (1122)-grown QDs exhibited pyramidal or truncated-pyramidal morphology consistent with the symmetry of the nucleating plane, and were delimited by nonpolar and semipolar nanofacets. It was also found that, in addition to the
Journal of the Korean Physical Society, 2008
We review our results on the growth of ZnTe-and CdTe-based nanowires (NWs) and on their basic str... more We review our results on the growth of ZnTe-and CdTe-based nanowires (NWs) and on their basic structural and optical properties. The nanowires were produced by using molecular beam epitaxy (MBE) with the use of a mechanism of catalytically-enhanced growth. The growth of ZnTe, CdTe, ZnMgTe and ZnMnTe nanowires was performed from elemental Zn, Cd, Mn, Mg and Te sources on the surfaces of (001)-, (110)-and (111)B-oriented GaAs substrates with Au nanocatalysts. The morphological and structural properties of the nanowires were assessed by using X-ray diffractometry, field-emission scanning electron microscopy, and high resolution transmission electron microscopy. Additional studies of the compositions of both the nanowires and the Au-rich nanocatalysts were performed with the use of energy dispersive X-ray spectroscopy. The optical properties of the NWs were assessed by using photoluminescence and Raman-scattering studies performed in both macro and micro modes. The studies revealed that binary and quaternary nanowires with average diameters from 30 to 70 nm and lengths from 1 to 2.6 µm were monocrystalline in their upper parts, their growth axis was 111 , and they grow along the [111] direction of the substrate, independent of the substrate orientation used. A Au-rich (with 20 % Ga) spherical nanocatalyst was always visible at the tip of a nanowire, thus indicating that a vapor-liquid-solid mechanism was responsible for the growth of the ZnTe-and the CdTe-based nanowires. The formation of homogeneous mixed crystal ZnMnTe and ZnMgTe nanowires was demonstrated by measurements of the variation of the lattice constant and by Raman experiments that revealed the expected shift and appearance of new phonon lines and a strong enhancement of the LO-phonon structures for an excitation close to the exciton energy of the NW materials. The photoluminescence from the internal Mn 2+ transition between crystal-field-split energy levels (4 T1 → 6 A1) was observed in the ZnMnTe nanowires.
We study an photoluminescence line of a single, self assembled CdTe quantum dot embedded in a fie... more We study an photoluminescence line of a single, self assembled CdTe quantum dot embedded in a field-effect structure. As a reverse bias is applied the line becomes broader and its intensity is decreased as a result of enhanced escape of the photocreated carriers. We account for the observed effects in a semiclassical model.
We report on the catalytically enhanced molecular beam epitaxial growth of Zn{sub 1-x}MnTe-based ... more We report on the catalytically enhanced molecular beam epitaxial growth of Zn{sub 1-x}MnTe-based nanowire structures, with manganese content up to x = 0.6, and on their basic structural and optical properties. The measurements that have been carried out confirm the incorporation of Mn{sup 2+} ions in the cation substitutional sites of ZnTe lattice.
We study the superconductor–insulator transition in Si/Nb/Si trilayers, in which the thickness of... more We study the superconductor–insulator transition in Si/Nb/Si trilayers, in which the thickness of Si is fixed at 10 nm, and the nominal thickness of Nb changes in the range between d = 20 nm down to d = 0.3 nm. The transmission electron microscopy indicates the formation of the mixed Nb–Si layer for small d. Both the thickness-induced, and the magnetic-field induced superconductor–insulator transition is observed. The crossing point of the isotherms at the critical field B c decreases with decreasing d, and it is T -independent at temperatures below 300 mK. At larger fields the weak peak in magnetoresistance appears in some of the films.
Acta Physica Polonica A - ACTA PHYS POL A, 2007
Catalytically enhanced growth of ZnMnTe diluted magnetic semiconductor nanowires by molecular bea... more Catalytically enhanced growth of ZnMnTe diluted magnetic semiconductor nanowires by molecular beam epitaxy is reported. The growth is based on the vapor-liquid-solid mechanism and was performed on (001) and (011)-oriented GaAs substrates from elemental sources. X-ray diffractometry, scanning and transmission electron microscopy, atomic force microscopy, photoluminescence spectroscopy, and Raman scattering were performed to determine the structure of nanowires, their chemical composition, and morphology. These studies revealed that the obtained ZnMnTe nanowires possess zinc-blende structure, have an average diameter of about 30 nm, typical length between 1 and 2 mum and that Mn2+ ions were incorporated into substitutional sites of the ZnTe crystal lattice.
physica status solidi (c), 2007
ABSTRACT By means of deep level transient spectroscopy (DLTS) a dislocation-related deep-level tr... more ABSTRACT By means of deep level transient spectroscopy (DLTS) a dislocation-related deep-level trap has been revealed in partially strain-relaxed InGaAs/GaAs heterostructures, grown by MOVPE. On the basis of the specific criteria containing DLTS-line shape and behaviour analysis as well as capture kinetics measurements, we were able to attribute the trap to “localized” states at the dislocation core or close to it. A direct comparison of DLTS concentration profiles and TEM results enable us to attribute the electron trap to 60° misfit dislocations lying at the heterostructure interface. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
physica status solidi (b), 2004
Investigation is carried out by high-resolution electron microscopy on threading dislocations usi... more Investigation is carried out by high-resolution electron microscopy on threading dislocations using data treatments with procedures that allow the extraction of the most likely atomic configurations. We also report In composition fluctuations inside InGaN/GaN quantum wells by coupling HRTEM, image simulation and Finite Element Modelling (FEM) of the thin foil relaxation. The results show that the indium content may be close to x = 1.0 in the clusters and this is much higher that was previously suggested by 2D FEM modelling.
Journal of Applied Physics, 2002
In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells... more In situ X-ray investigation of changing barrier growth temperatures on InGaN single quantum wells in metalorganic vapor phase epitaxy J. Appl. Phys. 115, 094906 (2014); 10.1063/1.4867640
Diamond and Related Materials, 2004
Films composed of Ni nanocrystals placed in an amorphous carbon matrix were investigated by photo... more Films composed of Ni nanocrystals placed in an amorphous carbon matrix were investigated by photoelectric methods. Information about the structure of Ni nanocrystals and the amorphous carbon matrix were obtained from TEM and Raman spectroscopy, respectively. The lowering of the photoelectric threshold (from 2.61 to 2.55 eV) as well as an increase of the photoelectric charge sensitivity after film cleaning with UV laser light was found.
Applied Physics Letters, 2005
ABSTRACT Formation of MnAs quantum dots in a regular ring-like distribution has been found on mol... more ABSTRACT Formation of MnAs quantum dots in a regular ring-like distribution has been found on molecular beam epitaxy grown (GaMn)As(100) surfaces after low-temperature annealing under As capping. The appearance of the dots depends on the thickness and Mn concentration in the (GaMn)As layer. With 5 at. % substitutional Mn the quantum dots showed up for layers thicker than 100 nm. For thinner layers the surfaces of the annealed samples are smooth and well ordered with 1×2 surface reconstruction, just as for as-grown (GaMn)As. The annealed surfaces are Mn rich, and are well suited for continued epitaxial growth.
GaN quantum dots (QDs) grown in semipolar (1122) AlN by plasma-assisted molecular-beam epitaxy we... more GaN quantum dots (QDs) grown in semipolar (1122) AlN by plasma-assisted molecular-beam epitaxy were studied by transmission electron microscopy (TEM) and scanning transmission electron microscopy techniques. The embedded (1122)-grown QDs exhibited pyramidal or truncated-pyramidal morphology consistent with the symmetry of the nucleating plane, and were delimited by nonpolar and semipolar nanofacets. It was also found that, in addition to the