S. Krukowski - Academia.edu (original) (raw)
Papers by S. Krukowski
International Journal of Materials and Product Technology, 2005
Thermodynamic and kinetic properties of group III metal nitrides Me(Al,Ga,In)N-Me(l)-N-2 systems ... more Thermodynamic and kinetic properties of group III metal nitrides Me(Al,Ga,In)N-Me(l)-N-2 systems are strongly influenced by the high binding energy of molecular nitrogen which favours the decomposition of these compounds into the constituents, severely limiting the growth possibilities of these crystals. From all three nitrides, the AIN sizeable crystals have been grown from the vapour only. In contrast, the best GaN
ChemInform, 2009
Inorganic chemistry Z 0100 Review: GaN Growth by Ammonia Based Methods -Density Functional Theory... more Inorganic chemistry Z 0100 Review: GaN Growth by Ammonia Based Methods -Density Functional Theory Study -[60 refs.]. -(KRUKOWSKI*, S.; KEMPISTY, P.; STRAK, P.; Cryst. Res.
physica status solidi (c), 2008
ABSTRACT Results of liquid phase epitaxy of GaN on MOCVD sapphire/GaN and HVPE free-standing GaN ... more ABSTRACT Results of liquid phase epitaxy of GaN on MOCVD sapphire/GaN and HVPE free-standing GaN substrates by high pressure solution method are presented. The finite element calculation using experimentally measured temperatures is used for modeling the convective transport in the liquid gallium. The influence of a baffle and thermal conductivity of the various seeds for convection in liquid metal is analyzed in details. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Journal of Physics: Condensed Matter, 2001
... p-type material. So far GaN crystals have been grown in the presence of Mg [8], Be [9], Ca [1... more ... p-type material. So far GaN crystals have been grown in the presence of Mg [8], Be [9], Ca [10], Zn [11] and Be together with Mg [12]. A variety of group II metal concentrations in liquid gallium have been used. As previously reported ...
Journal of Crystal Growth, 2005
In this work the results of high pressure solution growth of GaN on various patterned substrates ... more In this work the results of high pressure solution growth of GaN on various patterned substrates are presented. The growth on GaN/sapphire substrates patterned in GaN parallel stripes and with Si x N y and Mo masks between stripes is studied and analyzed. The results are compared with the growth on patterned substrates without any mask, thus with a bare sapphire between stripes. The usefulness of tungsten and iridium for masking is also determined. The HVPE free standing GaN substrates with high stripes, up to 10 µm, are examined in details. The stripes growth modes are shown and described.
Journal of Crystal Growth, 2007
Seeded growth of GaN on 1 in sapphire/GaN templates by high-pressure solution method is presented... more Seeded growth of GaN on 1 in sapphire/GaN templates by high-pressure solution method is presented. Five crystallization runs at the same growth conditions (temperatures, supercooling, nitrogen pressure, time) but different in geometry are described in details. The finite element calculation is used for modeling the convective transport in the liquid gallium. The stream lines, convectional flow velocity vectors and isotherm lines in liquid metal are determined based on experimentally measured temperatures in the crucible wall. The influence of the seed and the baffle for convection in liquid metal is analyzed in details. r
Journal of Crystal Growth, 2007
The growth of GaN needles by high-pressure solution method is described in detail and compared to... more The growth of GaN needles by high-pressure solution method is described in detail and compared to well-known platelets' crystallization. The habit, morphology and crystal quality of the needles are examined. The growth mechanism and main factors determining the crystal habit in high-pressure solution method are discussed. The needles' preparation to be the seeds for HVPE growth is presented. r
Journal of Crystal Growth, 2005
In this paper the results of directional high-pressure growth of GaN on sapphire/GaN MOCVD templa... more In this paper the results of directional high-pressure growth of GaN on sapphire/GaN MOCVD templates are described. The use of a baffle plate is presented, in order to obtain the flat crystallization front at the substrate. The GaN growth rate as a function of the applied temperature gradient and time is analyzed in detail. The optimal temperature gradient for the fastest growth is determined. The changes of the growth rate with time are explained. The defect selective etching method and transmission electron microscopy are used to determine the dislocation density in the deposited GaN material. All results are compared to those obtained for directional growth of GaN on pressure grown GaN crystals (platelets).
The Journal of Chemical Physics, 2008
GaN (0001) surface in an ammonia-rich vapor ambient, typical for ammonia annealing, metalo-organi... more GaN (0001) surface in an ammonia-rich vapor ambient, typical for ammonia annealing, metalo-organic vapor phase epitaxy (MOVPE) or hydride vapor phase epitaxy (HVPE) was considered. It was shown that, in these three cases, the stationary state of the surface corresponds to condition far from equilibrium. The chemical potential of nitrogen and hydrogen at the surface was determined using kinetic arguments, i.e., derived form the magnitude of flux of ammonia. For HVPE and MOVPE growth, the chemical potential of gallium depends on the distance from the steps. Thus, only far distance from the step value of the gallium chemical potential at the GaN(0001) surface could be determined in similar way. In the alternative case of GaN annealing in ammonia atmosphere, gallium chemical potential at the surface remains undetermined (the surface is in a metastable state). Additionally, using thermodynamic arguments, the limits for the chemical potential of gallium (upper) and nitrogen (lower) were formulated for the case of vapor growth, and expressed as functions of temperature and pressure. The results, regarding the atomic processes on the GaN(0001) surface, were obtained using the SIESTA, density functional theory based code, and consequently employed in the comparable thermodynamic and kinetic analysis of the state of GaN(0001) surface.
International Journal of Heat and Mass Transfer, 1992
Recently, non-axisymmetric convection in vertical directional solidification experiments has been... more Recently, non-axisymmetric convection in vertical directional solidification experiments has been observed. It has been suggested that the asymmetry is due to lack of azimuthal symmetry in imposed temperature and that the flow asymmetry will decrease with increasing velocities. Motivated by these observations we have examined the consequences of deviations from axisymmetric wall temperature conditions in a vertical differentially heated cylinder. We show that the degree of flow asymmetry depends on the ratio, A,, between the amplitudes of the maximum azimuthal and vertical temperature differences, and that for a fixed value of this ratio the flow asymmetry increases with increasing flow velocity (Rayleigh number). t Present address : Dtpartement de MathCmatiques et Mbcanique, case 322, Faculti: des Sciences et Techniques,
Crystal Research and Technology, 2005
Crystal Research and Technology, 2007
Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, densi... more Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, density functional theory. PACS 61.50.Ah, 81.10.Aj Surface properties and the principal processes at the growth of gallium nitride on GaN (0001) face in ammonia-based are modeled using DFT (density functional theory -SIESTA code) ab initio calculations and 2-d diffusion analysis. The GaN growth methods are: ammonia-source MBE, MOVPE, and also HVPE. The adiabatic trajectories, calculated for hydrogen-rich and hydrogen-free state of the GaN(0001) surface, include the adsorption of NH 3 , GaCl and HCl molecules and the desorption of Ga atoms. The adsorption of ammonia and GaCl has no energy barrier. Thus, in contrast to the results concerning Plasma-Assisted Molecular Beam Epitaxy (PA MBE), proving that the GaN(0001) surface remains in metal-rich state, these results indicate that, in the ammonia-rich environment, typical for HVPE and MOVP growth, the GaN(0001) surface remains in the nitrogen-rich state. In the case of HCl adsorption, the energy barrier depends on the surface coverage, and could reach 2.0 eV. The direct desorption of single Ga atom has the energy barrier, close to 7 eV. This indicates that Ga surface diffusion (growth controlling process) length is very large, leading to strong interaction of the step kinetics and the diffusion on the terraces. This interaction leads to double-step intertwined structures both in the case of dislocation-mediated spiral growth and in the step flow growth mode. These morphologies, proposed by the geometric arguments, are observed in the atomic force microscopy (AFM) scans of the GaN(0001) surface. Additionally we have compared the interaction energy of two hydrogen atoms obtained in the DFT SIESTA and the high precision Gaussian in coupled cluster singles, double and perturbation triples CCSD(T) approximation. Both approaches yielded virtually identical interaction energy confirming the validity of DFT analysis of ammonia-rich growth of GaN.
Crystal Research and Technology, 2009
Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, densi... more Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, density functional theory. PACS 61.50.Ah, 81.10.Aj
AIP Conference Proceedings, 1994
ABSTRACT
AIP Conference Proceedings, 1994
ABSTRACT
International Journal of Materials and Product Technology, 2005
Thermodynamic and kinetic properties of group III metal nitrides Me(Al,Ga,In)N-Me(l)-N-2 systems ... more Thermodynamic and kinetic properties of group III metal nitrides Me(Al,Ga,In)N-Me(l)-N-2 systems are strongly influenced by the high binding energy of molecular nitrogen which favours the decomposition of these compounds into the constituents, severely limiting the growth possibilities of these crystals. From all three nitrides, the AIN sizeable crystals have been grown from the vapour only. In contrast, the best GaN
ChemInform, 2009
Inorganic chemistry Z 0100 Review: GaN Growth by Ammonia Based Methods -Density Functional Theory... more Inorganic chemistry Z 0100 Review: GaN Growth by Ammonia Based Methods -Density Functional Theory Study -[60 refs.]. -(KRUKOWSKI*, S.; KEMPISTY, P.; STRAK, P.; Cryst. Res.
physica status solidi (c), 2008
ABSTRACT Results of liquid phase epitaxy of GaN on MOCVD sapphire/GaN and HVPE free-standing GaN ... more ABSTRACT Results of liquid phase epitaxy of GaN on MOCVD sapphire/GaN and HVPE free-standing GaN substrates by high pressure solution method are presented. The finite element calculation using experimentally measured temperatures is used for modeling the convective transport in the liquid gallium. The influence of a baffle and thermal conductivity of the various seeds for convection in liquid metal is analyzed in details. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Journal of Physics: Condensed Matter, 2001
... p-type material. So far GaN crystals have been grown in the presence of Mg [8], Be [9], Ca [1... more ... p-type material. So far GaN crystals have been grown in the presence of Mg [8], Be [9], Ca [10], Zn [11] and Be together with Mg [12]. A variety of group II metal concentrations in liquid gallium have been used. As previously reported ...
Journal of Crystal Growth, 2005
In this work the results of high pressure solution growth of GaN on various patterned substrates ... more In this work the results of high pressure solution growth of GaN on various patterned substrates are presented. The growth on GaN/sapphire substrates patterned in GaN parallel stripes and with Si x N y and Mo masks between stripes is studied and analyzed. The results are compared with the growth on patterned substrates without any mask, thus with a bare sapphire between stripes. The usefulness of tungsten and iridium for masking is also determined. The HVPE free standing GaN substrates with high stripes, up to 10 µm, are examined in details. The stripes growth modes are shown and described.
Journal of Crystal Growth, 2007
Seeded growth of GaN on 1 in sapphire/GaN templates by high-pressure solution method is presented... more Seeded growth of GaN on 1 in sapphire/GaN templates by high-pressure solution method is presented. Five crystallization runs at the same growth conditions (temperatures, supercooling, nitrogen pressure, time) but different in geometry are described in details. The finite element calculation is used for modeling the convective transport in the liquid gallium. The stream lines, convectional flow velocity vectors and isotherm lines in liquid metal are determined based on experimentally measured temperatures in the crucible wall. The influence of the seed and the baffle for convection in liquid metal is analyzed in details. r
Journal of Crystal Growth, 2007
The growth of GaN needles by high-pressure solution method is described in detail and compared to... more The growth of GaN needles by high-pressure solution method is described in detail and compared to well-known platelets' crystallization. The habit, morphology and crystal quality of the needles are examined. The growth mechanism and main factors determining the crystal habit in high-pressure solution method are discussed. The needles' preparation to be the seeds for HVPE growth is presented. r
Journal of Crystal Growth, 2005
In this paper the results of directional high-pressure growth of GaN on sapphire/GaN MOCVD templa... more In this paper the results of directional high-pressure growth of GaN on sapphire/GaN MOCVD templates are described. The use of a baffle plate is presented, in order to obtain the flat crystallization front at the substrate. The GaN growth rate as a function of the applied temperature gradient and time is analyzed in detail. The optimal temperature gradient for the fastest growth is determined. The changes of the growth rate with time are explained. The defect selective etching method and transmission electron microscopy are used to determine the dislocation density in the deposited GaN material. All results are compared to those obtained for directional growth of GaN on pressure grown GaN crystals (platelets).
The Journal of Chemical Physics, 2008
GaN (0001) surface in an ammonia-rich vapor ambient, typical for ammonia annealing, metalo-organi... more GaN (0001) surface in an ammonia-rich vapor ambient, typical for ammonia annealing, metalo-organic vapor phase epitaxy (MOVPE) or hydride vapor phase epitaxy (HVPE) was considered. It was shown that, in these three cases, the stationary state of the surface corresponds to condition far from equilibrium. The chemical potential of nitrogen and hydrogen at the surface was determined using kinetic arguments, i.e., derived form the magnitude of flux of ammonia. For HVPE and MOVPE growth, the chemical potential of gallium depends on the distance from the steps. Thus, only far distance from the step value of the gallium chemical potential at the GaN(0001) surface could be determined in similar way. In the alternative case of GaN annealing in ammonia atmosphere, gallium chemical potential at the surface remains undetermined (the surface is in a metastable state). Additionally, using thermodynamic arguments, the limits for the chemical potential of gallium (upper) and nitrogen (lower) were formulated for the case of vapor growth, and expressed as functions of temperature and pressure. The results, regarding the atomic processes on the GaN(0001) surface, were obtained using the SIESTA, density functional theory based code, and consequently employed in the comparable thermodynamic and kinetic analysis of the state of GaN(0001) surface.
International Journal of Heat and Mass Transfer, 1992
Recently, non-axisymmetric convection in vertical directional solidification experiments has been... more Recently, non-axisymmetric convection in vertical directional solidification experiments has been observed. It has been suggested that the asymmetry is due to lack of azimuthal symmetry in imposed temperature and that the flow asymmetry will decrease with increasing velocities. Motivated by these observations we have examined the consequences of deviations from axisymmetric wall temperature conditions in a vertical differentially heated cylinder. We show that the degree of flow asymmetry depends on the ratio, A,, between the amplitudes of the maximum azimuthal and vertical temperature differences, and that for a fixed value of this ratio the flow asymmetry increases with increasing flow velocity (Rayleigh number). t Present address : Dtpartement de MathCmatiques et Mbcanique, case 322, Faculti: des Sciences et Techniques,
Crystal Research and Technology, 2005
Crystal Research and Technology, 2007
Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, densi... more Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, density functional theory. PACS 61.50.Ah, 81.10.Aj Surface properties and the principal processes at the growth of gallium nitride on GaN (0001) face in ammonia-based are modeled using DFT (density functional theory -SIESTA code) ab initio calculations and 2-d diffusion analysis. The GaN growth methods are: ammonia-source MBE, MOVPE, and also HVPE. The adiabatic trajectories, calculated for hydrogen-rich and hydrogen-free state of the GaN(0001) surface, include the adsorption of NH 3 , GaCl and HCl molecules and the desorption of Ga atoms. The adsorption of ammonia and GaCl has no energy barrier. Thus, in contrast to the results concerning Plasma-Assisted Molecular Beam Epitaxy (PA MBE), proving that the GaN(0001) surface remains in metal-rich state, these results indicate that, in the ammonia-rich environment, typical for HVPE and MOVP growth, the GaN(0001) surface remains in the nitrogen-rich state. In the case of HCl adsorption, the energy barrier depends on the surface coverage, and could reach 2.0 eV. The direct desorption of single Ga atom has the energy barrier, close to 7 eV. This indicates that Ga surface diffusion (growth controlling process) length is very large, leading to strong interaction of the step kinetics and the diffusion on the terraces. This interaction leads to double-step intertwined structures both in the case of dislocation-mediated spiral growth and in the step flow growth mode. These morphologies, proposed by the geometric arguments, are observed in the atomic force microscopy (AFM) scans of the GaN(0001) surface. Additionally we have compared the interaction energy of two hydrogen atoms obtained in the DFT SIESTA and the high precision Gaussian in coupled cluster singles, double and perturbation triples CCSD(T) approximation. Both approaches yielded virtually identical interaction energy confirming the validity of DFT analysis of ammonia-rich growth of GaN.
Crystal Research and Technology, 2009
Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, densi... more Key words gallium nitride, hydrogen vapor phase epitaxy, metal organic vapor phase epitaxy, density functional theory. PACS 61.50.Ah, 81.10.Aj
AIP Conference Proceedings, 1994
ABSTRACT
AIP Conference Proceedings, 1994
ABSTRACT