Two different sizes of PbO nanoparticles, notably PbO(A) and PbO(B) with sizes of 78 nm and 54 nm... more Two different sizes of PbO nanoparticles, notably PbO(A) and PbO(B) with sizes of 78 nm and 54 nm, respectively are produced using a high-speed planetary ball milling machine under specific operating parameters. Following, the novel nanocomposite PS/PbO is synthesized using compression molding by embedding 10, 15, 25, and 35 wt% of PbO(Bulk), PbO(A) and PbO(B) into PS separately. The composite is further characterized by Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and laser-induced breakdown spectroscopy (LIBS). FTIR results confirm the presence of PbO, and indicate a physical adsorption of the nanoparticle onto the PS matrix surface. SEM, EDS and LIBS analyses reveal a more efficient diffusion of PbO in the PS matrix with the decrease of the nanoparticle size. On the other hand, Tensile and Vickers microhardness tests are performed to investigate the composite's mechanical properties. The st...
Journal of Inorganic and Organometallic Polymers and Materials, 2022
The new category of high-density polyethylene HDPE/WO3 was synthesized via compression molding te... more The new category of high-density polyethylene HDPE/WO3 was synthesized via compression molding technique. Various amounts (10, 15, 25, and 35 wt%) of bulk micro-sized WO3 (Sample A) and two selected WO3 nanoparticles 45 nm (Sample B) and 24 nm (Sample C) obtained through the mechanical process were used as filler to HDPE. The prepared composites with filler 15 and 35 wt% were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscope, and energy-dispersive X-ray. XRD and FTIR results exhibited that filler does not affect either the crystal or the chemical structure of HDPE, confirming the adsorption of the filler on the surface polymer matrix. The morphology exhibited a more uniform dispersion of WO3 nanoparticles in the HDPE polymer matrix at low filler weight fractions. The mechanical properties of the composites at all filler contents were investigated using Vickers microhardness and tensile stress–strain tests. The variation of Vickers microhardness Hv showed a reverse indentation size effect (RISE) and exhibited a noticeable increase with increasing the WO3 NPs(C) filler loading up to 25 wt%. The tensile test revealed an increase in Young’s modulus, ultimate tensile strength, and yield stress by the addition of either WO3 nanoparticles (B or C) to 25 wt%. Otherwise, any further increase in nano wt% filler induced a decrease in the elongation at break. This improvement, deduced in the mechanical properties of the nanocomposites, suggests promising applications in radiation shielding and industry such as coating, barriers, catalysis, photo corrosion, and photothermal conversion.
Journal of Radioanalytical and Nuclear Chemistry, 2017
This work presents a method for simultaneous proton induced gamma-ray emission analysis of fluori... more This work presents a method for simultaneous proton induced gamma-ray emission analysis of fluorine, lithium, and sodium in ''as received'' geological reference materials. 1.7, 2.4 and 3.0 MeV proton energies were chosen for this study. The choice of the most appropriate incident energy was made after the study of the variation of the signal/background ratio, the limit of detection, the duration of the analysis and the number of counts/lC for each element. Quantitative calculation was achieved using an external standard and the so-called E 1/2 analytical approach. For this purpose, the thick target yield of the gamma rays at 110, 197, 440 and 478 keV were given between 1.1 and 3.0 MeV proton energies.
This study is a multi-technique investigation of the Paris carbonaceous chondrite directly applie... more This study is a multi-technique investigation of the Paris carbonaceous chondrite directly applied on two selected 500 × 500 µm² areas of a millimetric fragment, without any chemical extraction. By mapping the partial hydration of the amorphous silicate phase dominating the meteorite sample matrix, infrared spectroscopy gave an interesting glimpse into the way the fluid may have circulated into the sample and partially altered it. The TOF-SIMS in-situ analysis allowed the studying and mapping of the wide diversity of chemical moieties composing the meteorite organic content. The results of the combined techniques show that at the micron scale, the organic matter was always spatially associated with the fine-grained and partially-hydrated amorphous silicates and to the presence of iron in different chemical states. These systematic associations, illustrated in previous studies of other carbonaceous chondrites, were further supported by the identification by TOF-SIMS of cyanide and/or...
Journal of Superconductivity and Novel Magnetism, 2016
Bulk polycrystalline samples of LaO 1 À x F x BiSe 2 (x ranges from 0 to 0.5) with nominal compos... more Bulk polycrystalline samples of LaO 1 À x F x BiSe 2 (x ranges from 0 to 0.5) with nominal composition have been successfully synthesized by solid state reaction. Detailed structural analysis shows that LaOBiSe 2 crystallizes in a tetragonal structure (P4/nmm) with lattice parameters of a ¼4.1565(1) Å and c ¼14.1074 (3) Å. Experimental results of electrical transport demonstrate that LaOBiSe 2 is a bad metal with an evident anomaly at about 120 K, while the magnetic susceptibility exhibits an evident anomaly around 120 K, suggesting a possible charge density wave (CDW) transition around this temperature. Furthermore, superconductivity is observed in LaO 0.5 F 0.5 BiSe 2 sample with nominal composition at 3.1 K from magnetic and transport measurements.
A typology and archaeometrical study of the late 1st-early 2nd century AD pottery workshop in Bei... more A typology and archaeometrical study of the late 1st-early 2nd century AD pottery workshop in Beirut: amphorae and kitchen wares.
The effects of the deposition temperature and laser energy on the characteristics of Co 2 MnAl fi... more The effects of the deposition temperature and laser energy on the characteristics of Co 2 MnAl films deposited on GaAs substrates were investigated. The grown films were characterized by AFM for film roughness and surface topography. Film thickness and elemental composition were measured using Rutherford Back Scattering (RBS) technique, while crystalline structure and phase composition were investigated by XRD. The RBS measurements showed that the stochiometry of the films was satisfactory and very close to that of the target Co: 0.5, Mn: 0.25, Al: 0.25. The thickness of the films was found to increase as the laser energy was increased from 200 to 400 mJ, in particular for the films deposited at 400 °C. We also found an increase in the films thicknesses as the deposition temperature was increased for the samples grown at 200 and 300 mJ. The best film quality as deduced from XRD, RBS and AFM results for producing these single layers were those deposited at 600 °C with the laser energy at 300 mJ.
Thin coatings of Tungsten were deposited on substrates fabricated by pre-depositing graphite thin... more Thin coatings of Tungsten were deposited on substrates fabricated by pre-depositing graphite thin layers on Si(100) wafers. We ablate pure W target using a 20 ns KrF excimer laser (248 nm) in an Ar ambient. The effect of background gas pressure, substrate temperature, and laser fluence, on the properties of the deposited W layers is studied using several techniques including X-Ray Diffraction, Atomic Force Microscopy, surface profilometry, and Rutherford Back-Scattering spectrometry. Our results indicate that the deposited layers consist of the well-crystallized body-centered-cubic α-W phase with bulk-like properties, particularly for films deposited at a substrate temperature of 450°C, laser fluence greater than 400mJ, and pressure of about 10mTorr.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2006
The quantification of the active ingredient (AI) in drugs is a crucial and important step in the ... more The quantification of the active ingredient (AI) in drugs is a crucial and important step in the drug quality control process. This is usually performed by using wet chemical techniques like LC–MS, UV spectrophotometry and other appropriate organic analytical methods. In the case of an active ingredient contains specific heteroatoms (F, S, Cl, etc.,), elemental IBA technique can be explored
In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a r... more In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a rapid, nondestructive and quantification of Boron in ultra-thin films of BxGa1-xAs deposited on GaAs substrate using MOCVD is discussed. In order to improve the sensitivity for B detection, a systematic study was undertaken using proton induced beam at three different energies (from 1.7, 2.4 and 3 MeV) with different tilting angles (0, 60° and 80°). Best conditions were found to be at 1.7 MeV and at 80° for proton energy and tilting angle within ten minutes of acquisition time.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2002
In this work the capability of the PIXE technique to monitor a rapid and accurate quantification ... more In this work the capability of the PIXE technique to monitor a rapid and accurate quantification of P in thin SiO 2 (P, B) CVD layers (400 nm) deposited onto silicon substrate is discussed. In order to improve the sensitivity for P determination, a systematic study was undertaken using protons and helium ion beams at different energies using different thickness of Kapton X-ray absorbers. 600 keV proton or 1.5 MeV helium under normal incidence, using 146 µm kapton as X-ray absorber, permits an accurate quantification of P with high sensitivity within few minutes of acquisition time. This sensitivity is highly improved when using grazing incidence angles (e.g. 80°), thus 1 MeV protons can be easily used. Finally, the PIXE results shows that the phosphorus concentration in the CVD layer varies linearly with the percentage of the phosphine gas used in the CVD gas mixture.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2010
PIXE and RBS analysis is used to investigate the elemental content of modern Lebanese coins, in o... more PIXE and RBS analysis is used to investigate the elemental content of modern Lebanese coins, in order to control their minting quality. The coins of interest were 100, 250 and 500 Lebanese Lira (LL), which are mainly bulky metals with or without coated layer. Using 3MeV protons, proton induced X-ray emission PIXE identified and quantified elements while Rutherford backscattering spectrometry
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2002
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Journal of Superconductivity and Novel Magnetism, 2009
Superconducting samples of type TlBa2Ca3−y Er y Cu4O11−δ and Cu0.25Tl0.75Ba2Ca3−y Er y Cu4O12−δ ,... more Superconducting samples of type TlBa2Ca3−y Er y Cu4O11−δ and Cu0.25Tl0.75Ba2Ca3−y Er y Cu4O12−δ ,y ranging from 0.0 to 0.1, have been prepared by a single step of solid-state reaction technique at normal pressure using high-purity oxide elements. The lattice parameters, for prepared samples, have been estimated from X-ray powder diffraction (XRD). The elemental stoichiometry of the prepared samples has been determined
Journal of Superconductivity and Novel Magnetism, 2009
Page 1. J Supercond Nov Magn (2009) 22: 495504 DOI 10.1007/s10948-009-0447-z ORIGINAL PAPER Ion ... more Page 1. J Supercond Nov Magn (2009) 22: 495504 DOI 10.1007/s10948-009-0447-z ORIGINAL PAPER Ion Beam Analysis and Physical Properties Measurements of (Tl0.8Hg0.2−xSbx)Ba2Ca2Cu3O9−δ AI Abou-Aly · NH ...
VLS mechanism was used for growing boron doped homoepitaxial SiC layers on 4H-SiC(0 0 0 1) 81 off... more VLS mechanism was used for growing boron doped homoepitaxial SiC layers on 4H-SiC(0 0 0 1) 81 off substrate. Si-based melts were fed by propane in the temperature range 1450-1500 1C. Two main approaches were studied to incorporate boron during growth: (1) adding elemental B in the initial melt, with two different compositions: Si 90 B 10 and Si 27 Ge 68 B 5 ; the growth was performed at 1500 1C; (2) adding B 2 H 6 to the gas phase during growth with a melt composition of Si 25 Ge 75 ; the growth was performed at 1450 1C. In most cases, the growth time was limited by liquid loss. The longest growth duration (1 h) was obtained when adding B 2 H 6 to the gas phase. In the case of Si 90 B 10 melt, the surface morphology exhibits large and parallel terraces whereas the step front is more undulated when adding Ge. Raman and photoluminescence characterizations performed on these layers confirmed the 4H polytype of the layers in addition to the presence of B, which results in a strong B-N donor-acceptor band. The thickness and the growth rate were determined by micro-Infrared spectroscopy. Particle Induced gray Emission (PIGE) was tentatively used to detect B incorporation inside the grown layers. These results were compared to SIMS measurements from which B concentration was found to vary from 10 18 to 10 19 at cm À 3 .
By a vapor-liquid-solid (VLS) mechanism, where a Ge-Si melt is fed by propane, 3C-SiC layers of ∼... more By a vapor-liquid-solid (VLS) mechanism, where a Ge-Si melt is fed by propane, 3C-SiC layers of ∼1.4 µm thickness were grown on 6H-SiC on-axis substrates. These layers were found to be single domain as seen from morphological and electron backscattering diffraction observations. They were free of any hexagonal inclusion. Both transmission electron microscopy and high-resolution X-ray diffraction show the high crystalline quality of the grown material. Nitrogen was found to be the main impurity, at a concentration of (6-7) × 10 17 cm-3 as estimated by Raman spectroscopy, though Al contamination was also detected by low-temperature photoluminescence. The identification and the quantification of Ge incorporation inside the SiC layers were determined by particle-induced X-ray emission (PIXE). The Ge concentration was calculated to be 5 × 10 18 atoms/cm 3 .
In this work the capability of the PIXE technique to monitor a rapid and accurate quantification ... more In this work the capability of the PIXE technique to monitor a rapid and accurate quantification of P in thin SiO 2 (P, B) CVD layers (400 nm) deposited onto silicon substrate is discussed. In order to improve the sensitivity for P determination, a systematic study was undertaken using protons and helium ion beams at different energies using different thickness of Kapton X-ray absorbers. 600 keV proton or 1.5 MeV helium under normal incidence, using 146 µm kapton as X-ray absorber, permits an accurate quantification of P with high sensitivity within few minutes of acquisition time. This sensitivity is highly improved when using grazing incidence angles (e.g. 80°), thus 1 MeV protons can be easily used. Finally, the PIXE results shows that the phosphorus concentration in the CVD layer varies linearly with the percentage of the phosphine gas used in the CVD gas mixture.
Two different sizes of PbO nanoparticles, notably PbO(A) and PbO(B) with sizes of 78 nm and 54 nm... more Two different sizes of PbO nanoparticles, notably PbO(A) and PbO(B) with sizes of 78 nm and 54 nm, respectively are produced using a high-speed planetary ball milling machine under specific operating parameters. Following, the novel nanocomposite PS/PbO is synthesized using compression molding by embedding 10, 15, 25, and 35 wt% of PbO(Bulk), PbO(A) and PbO(B) into PS separately. The composite is further characterized by Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and laser-induced breakdown spectroscopy (LIBS). FTIR results confirm the presence of PbO, and indicate a physical adsorption of the nanoparticle onto the PS matrix surface. SEM, EDS and LIBS analyses reveal a more efficient diffusion of PbO in the PS matrix with the decrease of the nanoparticle size. On the other hand, Tensile and Vickers microhardness tests are performed to investigate the composite's mechanical properties. The st...
Journal of Inorganic and Organometallic Polymers and Materials, 2022
The new category of high-density polyethylene HDPE/WO3 was synthesized via compression molding te... more The new category of high-density polyethylene HDPE/WO3 was synthesized via compression molding technique. Various amounts (10, 15, 25, and 35 wt%) of bulk micro-sized WO3 (Sample A) and two selected WO3 nanoparticles 45 nm (Sample B) and 24 nm (Sample C) obtained through the mechanical process were used as filler to HDPE. The prepared composites with filler 15 and 35 wt% were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscope, and energy-dispersive X-ray. XRD and FTIR results exhibited that filler does not affect either the crystal or the chemical structure of HDPE, confirming the adsorption of the filler on the surface polymer matrix. The morphology exhibited a more uniform dispersion of WO3 nanoparticles in the HDPE polymer matrix at low filler weight fractions. The mechanical properties of the composites at all filler contents were investigated using Vickers microhardness and tensile stress–strain tests. The variation of Vickers microhardness Hv showed a reverse indentation size effect (RISE) and exhibited a noticeable increase with increasing the WO3 NPs(C) filler loading up to 25 wt%. The tensile test revealed an increase in Young’s modulus, ultimate tensile strength, and yield stress by the addition of either WO3 nanoparticles (B or C) to 25 wt%. Otherwise, any further increase in nano wt% filler induced a decrease in the elongation at break. This improvement, deduced in the mechanical properties of the nanocomposites, suggests promising applications in radiation shielding and industry such as coating, barriers, catalysis, photo corrosion, and photothermal conversion.
Journal of Radioanalytical and Nuclear Chemistry, 2017
This work presents a method for simultaneous proton induced gamma-ray emission analysis of fluori... more This work presents a method for simultaneous proton induced gamma-ray emission analysis of fluorine, lithium, and sodium in ''as received'' geological reference materials. 1.7, 2.4 and 3.0 MeV proton energies were chosen for this study. The choice of the most appropriate incident energy was made after the study of the variation of the signal/background ratio, the limit of detection, the duration of the analysis and the number of counts/lC for each element. Quantitative calculation was achieved using an external standard and the so-called E 1/2 analytical approach. For this purpose, the thick target yield of the gamma rays at 110, 197, 440 and 478 keV were given between 1.1 and 3.0 MeV proton energies.
This study is a multi-technique investigation of the Paris carbonaceous chondrite directly applie... more This study is a multi-technique investigation of the Paris carbonaceous chondrite directly applied on two selected 500 × 500 µm² areas of a millimetric fragment, without any chemical extraction. By mapping the partial hydration of the amorphous silicate phase dominating the meteorite sample matrix, infrared spectroscopy gave an interesting glimpse into the way the fluid may have circulated into the sample and partially altered it. The TOF-SIMS in-situ analysis allowed the studying and mapping of the wide diversity of chemical moieties composing the meteorite organic content. The results of the combined techniques show that at the micron scale, the organic matter was always spatially associated with the fine-grained and partially-hydrated amorphous silicates and to the presence of iron in different chemical states. These systematic associations, illustrated in previous studies of other carbonaceous chondrites, were further supported by the identification by TOF-SIMS of cyanide and/or...
Journal of Superconductivity and Novel Magnetism, 2016
Bulk polycrystalline samples of LaO 1 À x F x BiSe 2 (x ranges from 0 to 0.5) with nominal compos... more Bulk polycrystalline samples of LaO 1 À x F x BiSe 2 (x ranges from 0 to 0.5) with nominal composition have been successfully synthesized by solid state reaction. Detailed structural analysis shows that LaOBiSe 2 crystallizes in a tetragonal structure (P4/nmm) with lattice parameters of a ¼4.1565(1) Å and c ¼14.1074 (3) Å. Experimental results of electrical transport demonstrate that LaOBiSe 2 is a bad metal with an evident anomaly at about 120 K, while the magnetic susceptibility exhibits an evident anomaly around 120 K, suggesting a possible charge density wave (CDW) transition around this temperature. Furthermore, superconductivity is observed in LaO 0.5 F 0.5 BiSe 2 sample with nominal composition at 3.1 K from magnetic and transport measurements.
A typology and archaeometrical study of the late 1st-early 2nd century AD pottery workshop in Bei... more A typology and archaeometrical study of the late 1st-early 2nd century AD pottery workshop in Beirut: amphorae and kitchen wares.
The effects of the deposition temperature and laser energy on the characteristics of Co 2 MnAl fi... more The effects of the deposition temperature and laser energy on the characteristics of Co 2 MnAl films deposited on GaAs substrates were investigated. The grown films were characterized by AFM for film roughness and surface topography. Film thickness and elemental composition were measured using Rutherford Back Scattering (RBS) technique, while crystalline structure and phase composition were investigated by XRD. The RBS measurements showed that the stochiometry of the films was satisfactory and very close to that of the target Co: 0.5, Mn: 0.25, Al: 0.25. The thickness of the films was found to increase as the laser energy was increased from 200 to 400 mJ, in particular for the films deposited at 400 °C. We also found an increase in the films thicknesses as the deposition temperature was increased for the samples grown at 200 and 300 mJ. The best film quality as deduced from XRD, RBS and AFM results for producing these single layers were those deposited at 600 °C with the laser energy at 300 mJ.
Thin coatings of Tungsten were deposited on substrates fabricated by pre-depositing graphite thin... more Thin coatings of Tungsten were deposited on substrates fabricated by pre-depositing graphite thin layers on Si(100) wafers. We ablate pure W target using a 20 ns KrF excimer laser (248 nm) in an Ar ambient. The effect of background gas pressure, substrate temperature, and laser fluence, on the properties of the deposited W layers is studied using several techniques including X-Ray Diffraction, Atomic Force Microscopy, surface profilometry, and Rutherford Back-Scattering spectrometry. Our results indicate that the deposited layers consist of the well-crystallized body-centered-cubic α-W phase with bulk-like properties, particularly for films deposited at a substrate temperature of 450°C, laser fluence greater than 400mJ, and pressure of about 10mTorr.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2006
The quantification of the active ingredient (AI) in drugs is a crucial and important step in the ... more The quantification of the active ingredient (AI) in drugs is a crucial and important step in the drug quality control process. This is usually performed by using wet chemical techniques like LC–MS, UV spectrophotometry and other appropriate organic analytical methods. In the case of an active ingredient contains specific heteroatoms (F, S, Cl, etc.,), elemental IBA technique can be explored
In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a r... more In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a rapid, nondestructive and quantification of Boron in ultra-thin films of BxGa1-xAs deposited on GaAs substrate using MOCVD is discussed. In order to improve the sensitivity for B detection, a systematic study was undertaken using proton induced beam at three different energies (from 1.7, 2.4 and 3 MeV) with different tilting angles (0, 60° and 80°). Best conditions were found to be at 1.7 MeV and at 80° for proton energy and tilting angle within ten minutes of acquisition time.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2002
In this work the capability of the PIXE technique to monitor a rapid and accurate quantification ... more In this work the capability of the PIXE technique to monitor a rapid and accurate quantification of P in thin SiO 2 (P, B) CVD layers (400 nm) deposited onto silicon substrate is discussed. In order to improve the sensitivity for P determination, a systematic study was undertaken using protons and helium ion beams at different energies using different thickness of Kapton X-ray absorbers. 600 keV proton or 1.5 MeV helium under normal incidence, using 146 µm kapton as X-ray absorber, permits an accurate quantification of P with high sensitivity within few minutes of acquisition time. This sensitivity is highly improved when using grazing incidence angles (e.g. 80°), thus 1 MeV protons can be easily used. Finally, the PIXE results shows that the phosphorus concentration in the CVD layer varies linearly with the percentage of the phosphine gas used in the CVD gas mixture.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2010
PIXE and RBS analysis is used to investigate the elemental content of modern Lebanese coins, in o... more PIXE and RBS analysis is used to investigate the elemental content of modern Lebanese coins, in order to control their minting quality. The coins of interest were 100, 250 and 500 Lebanese Lira (LL), which are mainly bulky metals with or without coated layer. Using 3MeV protons, proton induced X-ray emission PIXE identified and quantified elements while Rutherford backscattering spectrometry
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2002
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Journal of Superconductivity and Novel Magnetism, 2009
Superconducting samples of type TlBa2Ca3−y Er y Cu4O11−δ and Cu0.25Tl0.75Ba2Ca3−y Er y Cu4O12−δ ,... more Superconducting samples of type TlBa2Ca3−y Er y Cu4O11−δ and Cu0.25Tl0.75Ba2Ca3−y Er y Cu4O12−δ ,y ranging from 0.0 to 0.1, have been prepared by a single step of solid-state reaction technique at normal pressure using high-purity oxide elements. The lattice parameters, for prepared samples, have been estimated from X-ray powder diffraction (XRD). The elemental stoichiometry of the prepared samples has been determined
Journal of Superconductivity and Novel Magnetism, 2009
Page 1. J Supercond Nov Magn (2009) 22: 495504 DOI 10.1007/s10948-009-0447-z ORIGINAL PAPER Ion ... more Page 1. J Supercond Nov Magn (2009) 22: 495504 DOI 10.1007/s10948-009-0447-z ORIGINAL PAPER Ion Beam Analysis and Physical Properties Measurements of (Tl0.8Hg0.2−xSbx)Ba2Ca2Cu3O9−δ AI Abou-Aly · NH ...
VLS mechanism was used for growing boron doped homoepitaxial SiC layers on 4H-SiC(0 0 0 1) 81 off... more VLS mechanism was used for growing boron doped homoepitaxial SiC layers on 4H-SiC(0 0 0 1) 81 off substrate. Si-based melts were fed by propane in the temperature range 1450-1500 1C. Two main approaches were studied to incorporate boron during growth: (1) adding elemental B in the initial melt, with two different compositions: Si 90 B 10 and Si 27 Ge 68 B 5 ; the growth was performed at 1500 1C; (2) adding B 2 H 6 to the gas phase during growth with a melt composition of Si 25 Ge 75 ; the growth was performed at 1450 1C. In most cases, the growth time was limited by liquid loss. The longest growth duration (1 h) was obtained when adding B 2 H 6 to the gas phase. In the case of Si 90 B 10 melt, the surface morphology exhibits large and parallel terraces whereas the step front is more undulated when adding Ge. Raman and photoluminescence characterizations performed on these layers confirmed the 4H polytype of the layers in addition to the presence of B, which results in a strong B-N donor-acceptor band. The thickness and the growth rate were determined by micro-Infrared spectroscopy. Particle Induced gray Emission (PIGE) was tentatively used to detect B incorporation inside the grown layers. These results were compared to SIMS measurements from which B concentration was found to vary from 10 18 to 10 19 at cm À 3 .
By a vapor-liquid-solid (VLS) mechanism, where a Ge-Si melt is fed by propane, 3C-SiC layers of ∼... more By a vapor-liquid-solid (VLS) mechanism, where a Ge-Si melt is fed by propane, 3C-SiC layers of ∼1.4 µm thickness were grown on 6H-SiC on-axis substrates. These layers were found to be single domain as seen from morphological and electron backscattering diffraction observations. They were free of any hexagonal inclusion. Both transmission electron microscopy and high-resolution X-ray diffraction show the high crystalline quality of the grown material. Nitrogen was found to be the main impurity, at a concentration of (6-7) × 10 17 cm-3 as estimated by Raman spectroscopy, though Al contamination was also detected by low-temperature photoluminescence. The identification and the quantification of Ge incorporation inside the SiC layers were determined by particle-induced X-ray emission (PIXE). The Ge concentration was calculated to be 5 × 10 18 atoms/cm 3 .
In this work the capability of the PIXE technique to monitor a rapid and accurate quantification ... more In this work the capability of the PIXE technique to monitor a rapid and accurate quantification of P in thin SiO 2 (P, B) CVD layers (400 nm) deposited onto silicon substrate is discussed. In order to improve the sensitivity for P determination, a systematic study was undertaken using protons and helium ion beams at different energies using different thickness of Kapton X-ray absorbers. 600 keV proton or 1.5 MeV helium under normal incidence, using 146 µm kapton as X-ray absorber, permits an accurate quantification of P with high sensitivity within few minutes of acquisition time. This sensitivity is highly improved when using grazing incidence angles (e.g. 80°), thus 1 MeV protons can be easily used. Finally, the PIXE results shows that the phosphorus concentration in the CVD layer varies linearly with the percentage of the phosphine gas used in the CVD gas mixture.
Uploads
Papers by Mohamad Roumie